If x=5 and y=2 a solution of linear equation x+y=8​

Given

x=5   ,  y=2

x+y=5+2(2)=9

5x+2y=5(5)+2(2)=29

x+y=7

5x+y=5(5)+2=27

x=5,y=2 is solution of x+y=7