You take the first equation and make a value for y. So 6x + y =7 change it to : y = -6x + 7 Now in the second equation replace the “y” with -6x +7 this is what it means to use substitution method . Your combined equation will now be : 8x + 9(-6x + 7) =17 Now do distributive property and you get : 8x + -54x +63 =17 Now combine like terms ; -46x +63 =17 -46x =-46 x = 1 Now replace 1 for X value and we can get the value of Y . Y=1 X=1