x+y=8 y=3x substitution method.
super duper easy x + y = 8 if y = 3x then u substitute y(3x) + x = 8 4x = 8 x = 2 now you go BACK to y = 3x now substitute in the value of x (which we found) (3)(2) = y SOOO y = 6 x = 2
