A small square, with an increase of 8 centimeters in length, increases the area by 224 square centim

1.Let the side length of the small square be x

x+8)^2-x^2=224

x^2+16x+64-x^2=224

16x=160

x=102.Set x days later.

1/8x-1/12x=1/4

1/24x=1/4

x=63.Set B to take leave for x days.

1/20*16+1/30*(16-x)=148+32-2x=60

2x=20x=10

4.If there are x boys, then there will be 309-x girls.

309-x+25)+(1-5%)x=325334-x+

x=180 So there are 171 boys and 154 girls.

5.Assuming that 20% saline x g is required, then 5% brine (600-x) g is required.

20%x+5%(600-x)=15%*600x=400 so 400 grams of 20% saline, 200 grams of 5% saline.

6.The formula for summing the series of equal differences: sum (first term, last term) number of terms 27The quotient and remainder are x

13x+x>100

14x>100

x>100/14

and x<13 (the remainder is less than the divisor).

So 100 14 because x is an integer.

So x=8,9,10,11,12

There are 5 of them, which are 112, 126, 140, 154, 168, which must be common multiples of 11 and 13.

So this number is 285714

So the last four digits are 7029

11.Are there quite a few conditions that you are sure of?

So the concentration is:

13.Let the speed of the train be x meters and seconds, and the length of the train be y meters.

40x=440+y

30x=310+y

So 10x=130

x=13, y=80

Meter minutes = 2 meter seconds.

Let the train speed be x meters and seconds.

8(2+x)=288

16+8x=288x=34

1、(x+8)^2-x^2=224 【x=10】2、x[(1/8)-(1/12)]=`1/4 【x=6】3、(16-x)[(1/20)+(1/30)]+x(1/20)=1 【x=10】

4. The original students are 325-16=309; Set the original male x and female 309-x.

309+ [x=180] [171 males, 154 females] %*x+5%(600-x)=15%*600 [400g, 200g] 7, k 13=x+(x 13), then k=14x (8<=x<=12) [5].

Summary. 32 4 = 8 So the width is 8, and the circumference = (8 + 18) * 2 = 52 cm.

2. A rectangle, the length is 18 cm, if the length increases by 4 cm, the width remains the same, then the area increases by +32 square centimeters +

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A rectangle with a length of 18 centimeters, if the length increases by 4 centimeters and the width remains the same, then the area increases.

32 square centimeters. What was the original circumference of this rectangle?

32 4 = 8 So the width is 8, and the circumference = (8 + 18) * 2 = 52 cm.

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If the length of the original rectangle is ACM, the width is BCM (a, b is a natural number) (a+2) x (b + 7) - ab = 148Finishing 7a+2b=134a=18, b=4. a=16, b=11 eligible.

The original rectangle has an area of 18x4=72cm or 16x11=176cm

According to the meaning of the question, this problem can first set the unknown length as x, then according to the rectangle area formula s=a*b, 28*x=(28+4)*x-148, then x=148 4=37 cm, the original rectangle area s=28*37=1036 square centimeters.

Increased area = length and width.

Length = area increased in width.

37 cm. The area of the original rectangle = length and width.

1036 square centimeters.

If the width of a rectangle is 28 centimeters, the area increases by 148 square centimeters, and the area of the original rectangle is 1036 square centimeters.

If the width is increased by 4 cm, the area will increase by 148 square centimeters, and if the length remains the same, the length will be 148 4 = 37

The area of the original rectangle is 28x37 = 1036 square centimeters.

Let the length of the original rectangle be a centimeter, then the original area = 28, the area after the width is increased is (28 ten 4) = 28 + 148, and the solution is 4 = 148, = 37 centimeters, so the original area = 28x37 = 1036 square centimeters.

The width of the rectangle is increased by 4 cm, which is actually a rectangle that has increased the length to length and width to 4 cm, and the area of this rectangle is 148 square centimeters, so the length of the original rectangle is 148 4 37 cm, and the original area is 37 28 1036 square centimeters.

Rectangle area = length and width.

The width has increased by 4 cm, while the length has not changed, so you can find out what the length is.

148=length 4

Length = 148 4 = 37 (cm).

Knowing the length and width, you can use the rectangle area formula to find the area of the original rectangle.

37 28 = 1036 (square centimeters).

So the area of the original rectangle is 1036 square centimeters.

Suppose the length of the rectangle is x, according to the question 4x=148, x=37, the area of the rectangle is equal to the product of the length times the width, so 37 28=1036, answer: the area of the original rectangle is 1036 square centimeters.

If the width is increased by 4 cm, the area is increased by 148 square centimeters, and the length is 148 4 = 37 cm. Then the area of the original rectangle: 37 28 = 1036 square centimeters.

Solution: 148 4 28

1036 square centimeters.

A: The area of the original rectangle is 1036 square centimeters.

When the width of the rectangle is increased by 4 cm, the area increased is the area of the small rectangle. The length of the original rectangle can be found as:

148 4 = 37 (cm).

Then the area of the original rectangle:

37 28 = 1036 (square centimeters).

A: The area of the original rectangle is 1036 square centimeters.

The length of the rectangle is 148 4 = 37 cm, and the original area of the rectangle is 37 28 = 1036 square centimeters.

Length = 148 4 = 37 (cm).

The area of the original rectangle: 37 28 = 1036 square centimeters.

148 4 = 37 (cm).

37 28 = 1036 (square centimeters).

A: The area of the original rectangle is 1036 square centimeters.

The length of the rectangle:

148 4 = 37 (cm).

The area of the original rectangle:

37 cm 28 cm.

1036 square centimeters.

This question can be calculated like this:

148 4 = 37 (cm).

1036 square centimeters.

148 4 = 37, which is long.

Length and width are the original area.

Assuming that the side length of the square is a, then, a(a+8x2)=240+axa,—— solves, a=15, therefore, the area of the square is 15x15=225 square meters.

The original square side length = (32-2 2) 2 2 = 7 cm, the original square area = 7 7 = 49 square centimeters.

Area after increasing the side length by 4 cm = (7 + 4) (7 + 4) = 121 square centimeters, area increase = 121-49 = 72 square centimeters.

Let the original side length be xcm

(x+2) =x +32

The solution is x=7, so the side length of this square is 7cm

Hope it helps

The side length of the original square is 240 8 = 30 (meters).

The area of the original square is 30 30 = 900 (square meters).

The length of the original square is 240 (8 8) 15 meters, and the area of the original square is 15 15 225 meters.

The side length of the square is 8cm, then the area is 8x8=64 square centimeters, if the side length is increased by 25%, then the side length is 8x(1+25%)=10cm, then the area is 10x10=100 square centimeters, and the area increases by 100-64=36 square centimeters, I hope it will help you.

The side length of the original square is 8 cm, the area is 8x8 64 (square centimeters). If the side length is increased by 25, the side length becomes 8x(1 ten 25) cm. The area becomes 10x10 100 (square centimeters), which increases by 100-64 = 36 (square centimeters).

As shown in the figure below, the side length of the square is 8cm, if the side length increases by 25, how many square centimeters does the area increase?

8x8=64

8x(1+25%)=10

10x10=100

The area increased by 36 square centimeters.

The area of the first increase is: s1 + s2 + 8x8 = 384

The area of the second increase is: s1 + s2 + 4x8x8 = 384 + 3x8x8 = 576

With equations, it's very simple, and the following describes an arithmetic solution that combines graphs.

Draw a picture and see.

The length and width are increased by 8 cm to give a new rectangle, called the a-added part, which can be divided into 3 pieces.

One of them is a small square with a side length of 8 cm, with an area of 8 8 = 64 square centimeters, and the other two are two small rectangles, the width of the small rectangle, both 8 cm.

The length of the small rectangle is the length and width of the original rectangle, respectively.

The sum of the length and width of the original rectangle is:

384-64) 8 = 40 cm.

After adding 8 cm each, the sum of the length and width of the rectangle a is:

40 + 8 2 = 56 cm.

Then look at the picture...

The length and width are increased by 8 centimeters each, and a new rectangle is obtained, called the newly added part of b, which can still be divided into 3 pieces.

One of them is a small square with a side length of 8 cm, with an area of 8 8 = 64 square centimeters, and the other two are two rectangles, both 8 cm wide.

The lengths are the length and width of the rectangle a, respectively.

The increased area is:

56 8 + 8 8 = 512 square centimeters.

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Set the original rectangle long x cm wide y cm.

xy+384=(x+8)(y+8)

x+y=40

Then (x+8+8)(y+8+8)-(x+8)(y+8)=8(x+y)+3*64=512

Length A, Width B

a+8)(b+8)-ab=384

8(a+b)=384

a+b)=48

a+16)(b+16)-(a+8)(b+8)=ab+16(a+b)+256-ab-8(a+b)-64=8(a+b)+192

The area will increase by another 576 square centimeters.

512 set the length and width of the rectangle are a and b, and each increases by 8cm, then the increased area = 8 * a + 8 * b + 8 * 8 = 384

On this basis, add another 8cm, then increase the area = 8 * a + 8 * b + (8 + 8) * (8 + 8) - 8 * 8 = 512

The answer upstairs was incorrect.

Let the rectangle be originally a and b in length and width

then there is (a+8)(b+8)-ab=384

That is, 64 + 8 (a + b) = 384, a + b = 40 (a + 16) (b + 16) - (a + 8) (b + 8) = 192 + 8 (a + b) = 192 + 8 * 40 = 192 + 320 = 512 square centimeters.

384-8 8 = 320 square centimeters.

320 8 = 40 cm The sum of the original length and width.

40 + 8 2 = 56 cm Length, width and increased area after the first increase: 56 8 + 8 8 = 512 square centimeters.

。。。That's a good question ...

a+8)*(b+8)=ab+384

Solution: a+b=48

a+16)*(b+16)-(ab+384)=576