4.7x-(5x-5y)-y=______。

5.23 a3 BC 2- 15 ab2c+8 ABC-24 a3 BC 2-8 ABC = _ _ _ _ _ _。

6.-7x 2+6x+ 13 x2-4x-5x 2 = _ _ _ _ _ _。

7.2y+(-2y+5)-(3y+2)=______。

1 1.(2 x2-3xy+4 y2)+(x2+2xy-3 y2)= _ _ _ _ _ _。

12.2 a-(3a-2 b+2)+(3a-4 b- 1)= _ _ _ _ _ _。

13.-6x2-7x2+ 15x2-2x2=______。

14.2 x-(x+3y)-(-x-y)-(x-y)= _ _ _ _ _ _。

16.2 x+2y-[3x-2(x-y)]= _ _ _ _ _ _。

17.5-( 1-x)- 1-(x- 1)= _ _ _ _ _ _。

18.()+(4xy+7x2-y2)= 10x2-xy。

19.(4xy2-2x2y)-( )=x3-2x2y+4xy2+y3。

2 1. Given A=x3-2x2+x-4 and B=2x3-5x+3, calculate a+b = _ _ _ _.

22. given A=x3-2x2+x-4 and B=2x3-5x+3, calculate a-b = _ _ _ _.

23. If a=-0.2 and b=0.5, the value of the algebraic expression -(|a2b|-|ab2|) is _ _ _ _ _.

25. If a polynomial subtracts 3m4-m3-2m+5 to get -2m4-3m3-2m2- 1, then this polynomial is equal to _ _ _ _.

26.-(2 x2-y2)-[2 y2-(x2+2xy)]= _ _ _ _ _ _。

27. If -3a3b2 and 5ax- 1by+2 are similar terms, then x = _ _ _ _ _, and y = _ _ _ _ _.

28.(-y+6+3 y4-y3)-(2 y2-3 y3+y4-7)= _ _ _ _ _ _。

29. The result of simplifying the algebraic expression 4x2-[7x2-5x-3( 1-2x+x2)] is _ _ _ _.

30.2 a-B2+c-D3 = 2a+()-D3 = 2a-D3-()= c-()。

3 1.3a-(2a-3b)+3(a-2b)-b = _ _ _ _ _ _。

32. The simplified algebraic expression x-[y-2x-(x+y)] is equal to _ _ _ _.

33.[5a 2+()a-7]+[()a2-4a+()]= a2+2a+ 1。

34.3x-[y-(2x+y)]=______。

35.Simplify | 1-x+y |-x-y | (where x < 0, y > 0) equals _ _ _ _.

36. It is known that x≤y, x+y-| x+y-| x-y | = _ _ _ _ _

37. Given x < 0 and y < 0, simplify | x+y |-| 5-x-y | = _ _ _.

38.4a2n-an-(3an-2a2n)=______。

39. If you add -3x2y+2x2-3xy-4 to a polynomial, you get.

2x2y+3xy2-x2+2xy，

Then this polynomial is _ _ _ _.

40.-5xm-xm-(-7xm)+(-3xm)=______。

4 1. When a=- 1 and b=-2,

[a-(b-c)]-[-b-(-c-a)]=______。

43. When a=- 1, b= 1 and c=- 1,

-[b-2(-5a)]-(-3b+5c)=______。

44.-2(3x+z)-(-6x)+(-5y+3z)=______。

45.-5an-an+ 1-(-7an+ 1)+(-3an)= _ _ _ _ _ _。

46.3 a-(2a-4 b-6c)+3(-2c+2b)= _ _ _ _ _ _。

48.9 a2+[7 a2-2a-(-a2+3a)]= _ _ _ _ _ _。

50. When 2y-x=5, 5 (x-2y) 2-3 (-x+2y)-100 = _ _ _.