Question

计算5(x-1)(x+3)-2(x-5)(x-2)

Answer 1

解

5(x-1)(x+3)-2(x-5)(x-2)

=5(x²+3x-x-3)-2(x²-2x-5x+10)

=5(x²+2x-3)-2(x²-7x+10)

=(5x²-2x²)+(10x+14x)+(-15-20)

=3x²+24x-35

3(x+5)(x-3)-5(x-2)(x+3)

=3(x²+2x-15)-5(x²+x-6)

=(3x²-5x²)+(6x-5x)+(-45+30)

=-2x²+x-15