化简:-3{y-(3x^2-3xy)}-{y+2(4x^2-4xy)}
问题描述:
化简:-3{y-(3x^2-3xy)}-{y+2(4x^2-4xy)}
版本
答
-3{y-(3x^2-3xy)}-{y+2(4x^2-4xy)}
=-3{y-3x^2+3xy}-{y+8x^2-8xy}
=-3y+9x^2-9xy-y-8x^2+8xy
=x^2-xy-4y