Question

数学计算题系列（每集五道）1.x^3-7·x^2-4x+282.2·x^3-x^2-2x+13.ab(x^2+1)+x(

Answer 1

1.=x^2(x-7)-4(x-7)

=(x^2-4)(x-7)

=(x+2)(x-2)(x-7)

2.=x^2(2x-1)-(2x-1)

=(x^2-1)(2x-1)

=(x+1)(x-1)(2x-1)

3.=abx^2+ab+a^2x+b^2x

=ax(bx+a)+b(a+bx)

=(ax+b)(bx+a)

4.=x^2(x+a)-b^2(x-a

5.=a^2-a+0.25-b^2

=(a-0.5)^2-b^2

=(a-0.5+b)(a-0.5-b)