如果(3x+3y+1)(3x+3y-1)=63,那么x+y的值是?

问题描述:

如果(3x+3y+1)(3x+3y-1)=63,那么x+y的值是?

(3x+3y+1)(3x+3y-1)=(3X+3Y)²-1=63,则9(x+y)²=64,x+y=±8/3