How to do the new junior high school math summer homework?

1. Original formula = 3 (x-2y) 2-7 (x-2y) = (x-2y) (3x-6y-7), bring in x, y branches, and get 26

2. Polynomial = (2m-1) x 2+2y+8, independent of x value, so 2m-1=0, so, m=1 2, so the algebraic formula is found.

m^2+4m-4=-9/4

x 2+my-8-(-nx 2+2y+7)=(3+n)x 2+(m-2)y-15 does not contain x, y, so 3+n=0, n=-3 m-2=0 m=2

So n m+mn=(-3) 2-3*2=3

Solution 1 begins with the common factor (x-2y).

If we simplify and bring in x y, the original formula is equal to 0

Solution 2 simplification: (2mx -y+5x+8)-(x -3y+5x)(2m-1)x*-4y+8

Because it has nothing to do with the value of x.

m=1 2 is brought into the equation to get -9 4

Solution 33(x-2y) -7(x-2y)=(x-2y)(3x-6y-7)=0

m=1/2m²-（2m²-（5m-4）+m）=-9/4n=-3,m=2

n^m+mn=-8-6=-14

1.Original formula = 3 (x-2y) -7 (x-2y) x = -1, y = 1 2

x-2y=-1-2×1/2=-2

Substitute the original formula.

Original = 3 (-2) -7 (-2).

2.Original = (2m-1) x 2+2y+8

The value of 2mx -y+5x+8)-(x -3y+5x) is independent of x.

2m-1=0 m=1/2

m²-（2m²-（5m-4）+m）

Original = -m +4m-4

m-2) m=1 2 substitution.

3.According to the title:

3x²+my-8-(-nx²+2y+7)

Original = (3+n)x +(m-2)y-15

The difference of 3x +my-8-(-nx +2y+7) does not contain x, y3+n=0 m-2=0 n=-3 m=2

n^m+mn

n=-3 m=2 substitution.

Original = (-3) 2+2 (-3).

or n m + mn = n ((n m - 1) + m).

Substituting yields =-3 ((3 2-1)+2).

The first question, x, y can be substituted, calculated, equal to 50

Merge items of the same kind.

3（x-2y）²-7（x-2y）

The first question, substitution, the result is: 0;

(1)35 (35+x)*100%=15%(2) Let y=k (2x+1), substitute x=1, y=2 into the above equation to get k=2 3, so the relation is y=2 3(2x+1).

3) The three angles are 30°, 60°, and 90° respectively, so the three-sided ratio is 1: the root number is 3:2, and B is selected

Good luck with your studies!

1. 35/(35+x)=15%

2. y=6/(2x+1)

3.b Absolutely.,Don't learn from me downstairs.。。 Hope the above can help you...

It seems that just mention an x, it won't-. -

1）(x+y)(x+y-2x)=y^2-x^2(2) -x^2

9 (2) Except for mentioning (x+y) I really won't-. -10 in parentheses after the last 2 mentions (x-y) get 2y 2, and the final answer is y 2

Correct your two mistakes.

1. It's winter vacation, not summer vacation (if you cross it, of course, another story).

2 These questions are not to be calculated, but to be factored.

Factorization.

I won't ask for details.

x-3=0

x=3 y=3

3x-2y+2=9-6+2=5

2.（-2）*x=4-4x=-2+x x=6/5240 480

Save 4860-4120=740 yuan.

2) Buying all 45 does not meet the meaning of the topic (can't be calculated, the unknown number is eliminated), so 50x+45(103-x)=4860

x=45 then another class = 58

5 (180 240 480) Buy tickets together for two classes, save 4860-40*103=140 yuan, and the number of people is 45 58

5. Yes, saving 740 yuan, 58 people in 1 class and 45 people in 2 classes.