问题
填空题
计算:3x(2x-5y)=______;(a-1)(a-2)=______.
答案
3x(2x-5y)=3x•2x-3x•5y=6x2-15xy;
(a-1)(a-2)=a2-2a-a+2=a2-3a+2.
故应填:6x2-15xy,a2-3a+2.
计算:3x(2x-5y)=______;(a-1)(a-2)=______.
3x(2x-5y)=3x•2x-3x•5y=6x2-15xy;
(a-1)(a-2)=a2-2a-a+2=a2-3a+2.
故应填:6x2-15xy,a2-3a+2.