(4r^2+7r)+(-r^2+3r-1)计算
问题描述:
(4r^2+7r)+(-r^2+3r-1)计算
答
(4r^2+7r)+(-r^2+3r-1)
=4r^2+7r-r^2+3r-1
=3r^2+10r-1