提公因式数学题

Question

【a+b]²-【a-b]² 化简

已知道A+b=2 求A²-b²+4b

3a²b²-6ab²+3ab² 分解

Answer 1

解：
[a+b]²-[a-b]²=[a+b+a-b][a+b-a+b]=2a*2b=4ab

A²-b²+4b=a²- b²+4b-4 +4
=a²-(b²-4b+4) +4
=a²-(b-2)²+4
=(a+b-2)(a-b+2)+4 由于a+b=2 则 a+b-2=0
=0*(a-b+2)+4
=4

3a²b²-6ab²+3ab²
=3ab²(a-2+1)
=3ab²(a-1)

Answer 2

(a+b)²-(a-b)²
=[(a+b)+(a-b)][(a+b)-(a-b)]
=(2a)(2b)
=4ab

a+b=2
a²-b²+4b
=(a+b)(a-b)+4b
=2(a-b)+4b
=2a-2b+4b
=2a+2b
=2(a+b)
=2×2
=4

3a²b²-6ab²+3ab²
=3a²b²-3ab²
=3ab²(a-1)

Answer 3

【a+b]²-【a-b]² =a²+2ab+b²-a²+2ab-b²=4ab
a+b=2
a=2-b
a²-b²+4b
=(2-b)²-b²+4b
=4+b²-4b-b²+4b
=4
3a²b²-6ab²+3ab²
=3ab²(a-2+1)
=3ab²(a-1)

Answer 4

【a+b]²-【a-b]² 化简

=4ab
A+b=2 求A²-b²+4b

A²-b²+4b

=(A+b)(A-b)+4b
=2(A-b)+4b
=2(A+b)
=4

3a²b²-6ab²+3ab²

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

Answer 5

1.完全平方公式
a²+2ab+b²-(a²-2ab+b²)
=a²+2ab+b²-a²+2ab-b²
=4ab
2.a=2-b
(2-b)²-b²+4b
=4-4b+b²-b²+4b
=4
3.3ab²(a-1)

Answer 6

1、4ab
2、2(a-b)+4b=2a+2b=4
3、解：原式=3ab²(a-2+1)
=3ab²(a-1)