分类：教育/科学-学习帮助
问题：急求因式分解答案1.a^3*b^2
1.a^3*b^2-4a
2.-4x^3+8x^2-4x
3.(2x+3)^2-x^2
4.(y-3)(y+4)+49/4
回答：1.a^3*b^2 - 4a = a(a^2b^2 - 4) = a(ab + 2)(ab - 2)

2.-4x^3 + 8x^2 - 4x = -4x(x^2 - 2x + 1) = -4x(x - 1)^2
 
3.(2x + 3)^2 - x^2  = (2x + 3 + x)(2x + 3 - x) = 3(x + 1)(x + 3)

4.(y - 3)(y + 4) + 49/4 
= y^2  + y - 12 + 49/4 
= y^2  + y  + (1/2)^2 - (1/2)^2 - 12 + 49/4
 = (y + 1/2)^2