已知x+5y=6,求x(x+5y)+30y的值

问题描述:

已知x+5y=6,求x(x+5y)+30y的值

36,x(x+5y)+30y=6x+30y
因为x+5y=6,所以上式又等于6(x+5y)=36

x(x+5y)+30y
=6x+30y
=6(x+5y)
=6x6
=36