已知a+b=2,ab=-3 2【ab+(-3a0】-3(2b-ab)=?
问题描述:
已知a+b=2,ab=-3 2【ab+(-3a0】-3(2b-ab)=?
只要结果 要正确
答
2[ab+(-3a)]-3(2b-ab)
=2ab-6a-6b+3ab
=-6(a+b)+5ab
=-6×2+5×(-3)
=-12-15
=-27