计算18(4x²-xy)-19(4x²-xy)+(4x²-xy-1),
问题描述:
计算18(4x²-xy)-19(4x²-xy)+(4x²-xy-1),
答
18(4x²-xy)-19(4x²-xy)+(4x²-xy-1)
=72x²-18xy-76x²+19xy+4x²-xy-1
=-4x²+xy+4x²-xy-1
=-1