Question

去括号合并同类项，各位大侠帮帮忙

3乘b的二次方-（a的二次方+b的二次方）-b的二次方
x（2x-1)-(x/3+3)
-2(ab-3乘a的二次方）+（5ab-a的二次方）
2乘a的二次方-1/2(ab+a的二次方）-8ab
-(b-4)+4(-b-3)
1/2(x的二次方-y)+1/3(x-y的二次方）+1/6(x的二次方+y的二次方）

Answer 1

1:3b^2-(a^2+b^2)-b^2
=3b^2-a^2-b^2-b^2
=b^2-a^2
2:x(2x-1)-(x/3-3)
=2x^2-x-x/3+3
3:-2(ab-3a^2)+5ab-a^2
=-2ab+6a^2+5ab-a^2
=5a^2-3ab
4:2a^2-1/2(ab+a^2)-8ab
=2a^2-ab/2-a^2/2-8ab
=3a^2/2-17ab/2
5:-(b-4)+4(-b-3)
=-b+4-4b-12
=-5b-8
6:(x^2-y)/2+(x-y^2)/3+(x^2+y^2)/6
=x^2/2-y/2+x/3-y^2/3+x^2/6+y^2/6
=2x^2/3-y^2/6+x/3-y/2

Answer 2

1）3b^2-(a^2+b^2 )-b^2
=3b^2-a^2-b^2-b^2
=b^2-a^2

2）x(2x-1)-(1/3 x+3)
=2x^2-x- 1/3 x-3
=2x^2-4/3 x-3

3）-2(ab-3a^2 )+(5ab-a^2)
=-2ab+6a^2+5ab-a^2
=5a^2+3ab

4）2a^2-1/2 (ab+a^2 )-8ab
=2a^2-1/2 ab- 1/2 a^2-8ab
=3/2 a^2-17/2 ab

5）-(b-4)+4(-b-3)
=-b+4-4b-12
=-5b-8

6）1/2 (x^2-y)+1/3 (x-y^2 )+1/6(x^2+y^2)
=1/2 x^2-1/2 y+1/3 x- 1/3 y^2+1/6 x^2+1/6 y^2
=2/3 x^2-1/6 y^2+1/3 x-1/2 y

Answer 3

1 b^2-a^2
2 2x^2-x-x/3+3
3 5a^2-3ab
4 3a^2/2-17ab/2
5 -5b-8
6 2x^2/3-y^2/6+x/3-y/2