Y x 6 y 3x substitution July 8, 2019 16 32 64 128 3x y 12 and x y 6 substitution method Solve the system by substitution y x 6 y 3x X 6 y 6 3x 8 y 5 by substitution method X 6 y 6 3x 8 y 5 by substitution X 6 y 6 3x 4 1 y by substitution method (x+y) 3