Solve prep math problems, prep grade math problems to solve

2) (-13 1 2) 5+ (7/8) 5+

Satisfied. Wings of the Firmament answers for you.

1)-53 (1/23-1/76) +76 (1/23-1/53)+23 (1/53+1/76)

53 1/23 + 76 1/23) + (53 1/76 + 23 1/76) + (76 1/53 + 23 1/53).

53+76) 1/23 + (53+23) 1/76 + (-76+23) 1/53

23 1/23 + 76 1/76 + (-53) 1/53

2) (-13 and 1/2) 5+ (7/8) 5+

Time questions are OK for the first question first

I write the process directly, -53x1 23+73x1 23+53x1 76+23x1 76-76x1 53+23x1 53 (multiplicative distribution rate).

1 23x(-53+76)+1 76x(53+23)+1 53x(-76+23) (extract common factor).

1/23x23+1/76x76+1/53x-53

Add 3 people to divide into a group of 8 people and a group of 12 people.

There are more than 150 students and less than 200 students in the preparatory year.

24x7=168

24x8=192

Number of people: 168-3=165 (people).

Or: 192-3=189 (person).

The cost price is increased by 4%, that is, the price is 1 + 40% = 140% of the cost price, and the 80% discount of the price is 140% x 80% = 112%.

112%-1=12%This is the score corresponding to 24 yuan: 24 12%=200 (yuan).

A: The cost price of this kind of leather shoes is 200 yuan.

If the cost price is a yuan, then there is (1+40%) x 80%a-a=24

Solution: a=200

A: The cost price of this kind of leather shoes is 200 yuan.

Look at it**, I can't score it here, looking at the fractions you wrote, my head is dizzy, hehe

1 and 5/7

18 and 5/12

12/13

1.The total is 1

1 - 1/4 - 1/5 = 1/20.

2.The second year of junior high school: 360 * (1 + one-sixth) = 420 people.

Total: 360 + 420 = 780 people.

1) A pile of fruit, first a quarter of the total, then a fifth of the total, and eleven twentieths of the total

2) There are 360 students in the first year of junior high school, and one-sixth more students in the second year of junior high school than in the first year of junior high school, with a total of 780 students in these two grades.

（x+1）(x-5)

Multiply with crosses.

x term constant term.

Multiply the crosses and you can find it.

x^2-4x-5=（x-5）（x+1）

You can get it with a multiplication.

Solution: (1) Matching method.

Original = x 2-2x*2+2 2-2 2-5=(x 2-2*x*2+2 2)-(2 2+5)=(x-2) 2-9

x-2)^2-3^2

x-2+3)(x-2-3)

x+1)(x-5)

2) Cross multiplication.

x^2=x*x,-5=1×(-5),-4=1+（-5)∴x -5

x +1 original = (x+1) (x-5).

3) Split method.

Original = x 2-4x-5

x^2-4x-（4+1）

x^2-4x-4-1

x^2-1-4x-4

x^2-1)-(4x+4)

x+1)(x-1)-4(x+1)

x+1)(x-1-4)

x+1)(x-5)

4) Additive method.

Original = x 2-4x-5

x^2-(5x-x)-5

x^2-5x+x-5

x^2-5x)+(x-5)

x(x-5)+(x-5)

x+1)(x-5)

Note: 2 represents the square (power of the two) and * represents the multiplication sign.

This is also called high difficulty???

It seems to be the most rudimentary.

I can see at a glance how to do it.

x -5x +1

Therefore: (x-5) (x+1) give points.

What do you use it for?

It's better to find a few typical ones, we learn the method rather than the quantity.