求x平方-29x+10y与x平方+13x-5y的2倍的差

问题描述:

求x平方-29x+10y与x平方+13x-5y的2倍的差

x2-29x+10y-2(x2+13x-5y)
=x2-29x+10y-5x2-26x+10y
=x2-55x+20y