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The first volume of seventh grade mathematics in Beijing
1. For example:-1

2. Let this polynomial be m, and from m+x 2+ 14x-6 = 2x 2-x+3, we can deduce m = x 2- 15x+9.

m-(x^2+ 14x-6)=-29x+ 15

4.-AB (1+1/2x2)-1/5x32 binomial coefficient-1/2ab- 1/52 and 3 times.

If the three terms XY-PQX 2+(5/9P 3+9) X are unknown, there are three terms Y -PQ 1 twice.

5.-(a^5-6b)-(-7+3b)=-a^5+6b+7-3b=-a^5+3b+7

6. 1/4(-4x^2+2x-8)-( 1/2x- 1)=-x^2+ 1/2x-2- 1/2x+ 1=-x^2- 1=-5/4

7.A=a^2-2ab+b^2 B=a^2+2ab+b^2

a+b=2a^2+2b^2 1/4(b-a)= 1/4(4ab)= ab

2A-3B+C=0

-a^2- 10ab-b^2+C=0

c=a^2+ 10ab+b^2

8. 1. I don't understand 2.-2mn-2m+3n-73。 -A 2-8a+ 1 1d 3-2b 3。

4.2AB+3B^2-5-3AB-3B^2+8=3-AB