求(3x-2)(x-3)-2(x+6)(x-5)+3(x-7x+13)的值
问题描述:
求(3x-2)(x-3)-2(x+6)(x-5)+3(x-7x+13)的值
答
漏了x²把
原式=(3x²-11x+6)-2(x²+x-30)+3x²-21x+39
=3x²-11x+6-2x²-2x+60+3x²-21x+39
=4x²-34x+105