Math Masters Help Me! Math masters, help!

One. Calculation [have a process].

8 and 3/8 - 2/5

3/4 II. Columnar calculation [solved with equations].

3 times more than 8 and 1/2 5, find x.

3x=8 and 1 2+5

3x=x=5/8 of a number is more than 1/2 of 19, find this number.

Let this number be x

x*5/8=19*1/2+

5/8x=x=3.More than 3/5 of a number, find this number.

Let this number be x

3/5x=x=44.2/5 of a number is 1 smaller than the largest two-digit number, find this number.

Let this number be x

x*2/5=99-1

2/5x=98

x = divided by 3/5 quotient multiplied by 1 minus 2/3 difference, what is the product? [You can solve it without equations].

5 and 5 is more than 3/5 of a number, what is this number?

Let this number be x

What is the difference between 1/5 of x = 4 and 1/2 divided by 3?

1 2 3

What is the quotient of 25 percent divided by 1/2 versus 1/3 of the sum?

After A does AE parallel to CB, then the problem can be solved to find the size of the angle DAE (for the time being, it is an acute angle by default), so.

CB AE, then CBA= EAD, and CBA=40° then EAD=40°. Therefore, it is sufficient to bend 40° upwards (clockwise) at the AD edge point A.

In addition, it can also be known that a 140° downward (counterclockwise) bend of the edge point A can also be parallel to BC. Hope!

Do auxiliary line AE parallel BC because the angle b = 40 degrees, so the angle dae also = 40 degrees (two straight lines are parallel, the isotopic angle is equal).

So it should bend 40 degrees towards BC.

Upstairs is the teacher??

Let the function f(x)=2x -4x+a+1, from the analytic expression of the function, it can be seen that the parabolic opening of the function image is upward, to make one of the equations greater than 2 and the other less than 2, only f(2)<0, that is, 2 2 -4 2+a+1<0, we get a< -1

First of all, because the equation has two roots, so b 4ac 0. Gives a 1 and then the axis of symmetry of the equation curve x = b 2a = 2 Therefore, the root of the equation will be: one root is greater than 2 and the other is less than 2, hence a 1

Can!! I'm a teacher, and I hope you're happy with the answers.

f(x)=2x-4x+a+1 opens upward, and the axis of symmetry x=1 can be seen from the image.

One root is greater than 2 and the other root is less than 2

then f(2)=a+1<0

a<-1

Use the combination of numbers and shapes;

Let f(x)=2x -4x+a+1

f(x)= when there are two different roots, then the discriminant is greater than a 1 that can be solved

The axis of symmetry of the function image is x=1

The landlord can draw a rough picture of the function.

From the parabolic symmetry, it can be seen that the other is less than 0

Therefore, two more formulas f(0) 0;

f（2）＜0

The combination of three formulas can be solved to obtain a -1

(-a+1)The solution set of x a-1 is x -1

a-1）*（x）＞a-1

Since x -1, so -x 1

Hence -x (a-1) (a-1).

Note A-1 0

So a 1

Let the area of each unit be 1

The number of small rectangles containing only a is: 1, s 1;

The number of other small rectangles with 1 small rectangle is 4, the number of s 4*2 8 and 2 small rectangles is total: 4, the number of s 3*4 12 and 3 small rectangles is total:

6, s 4*6 24 with 5 small rectangles in total: 8, s 8*6 48 in addition, s 8 * 6 48 in addition, s 4 in addition, s 4 * 8 32 in addition to 8 small rectangles in total quantity:

1, s 1*8 8 with 11 small rectangles in total: 4, s 12*4 48 in the number of 15 small rectangles in total: 1, s 1*16 16 in total:

33 areas: 197

21 How do you calculate the area without edge length???

Let these four numbers be x1, x2, x3, and x4 respectively, then we have:

x1+x3=2*x2...1)x3^2=x2*x4...2)x1+x4=16...

3)x2+x3=12...4) The joint solution of the equation obtains: these four numbers are ; Or.