X y 7 2x y 9 July 8, 2019 16 32 64 128 X 2 y 7 2x 6 y 9 X 2y 7 2x y 9 X y 7 2x 3y 9 X y 7 2x 3y 9 by graphical method X y 7 2x 3y 9 substitution method X y 7 2x 3y 9 by cramer's method 2x 3 y 7 x 9 y 4