Question

x的平方减Y的平方等于12,X加Y等于6,求X,Y的值

Answer 1

X²-Y²=12,即(X+Y)(X-Y)=12.

又X+Y=6,则X-Y=2.

故(X+Y)+(X-Y)=6+2,即2X=8,X=4;

所以,Y=6-X=2.