(x-2)(x-3)+2(x+6)(x-5)-3(x^2-7x+13)
问题描述：
(x-2)(x-3)+2(x+6)(x-5)-3(x^2-7x+13)
答
=x²-5x+6+2(x²+x-30)-3(x²-7x+13)
=x²-5x+6+2x²+2x-60-3x²+21x-39
=18x-93