(1) 2x + 3y = 31 y
(2) 2x + 3y = x + 7
(3) 31y = x + 7
(3) x = 31y - 7
(2) 2(31y - 7) + 3y = 31y - 7 + 7 ; 62y - 14 + 3y = 31y ; 34y = 14 ; y = 14/34 ; y = 7/17
(3) x = 31y - 7 ; x = 31*(7/17) - 7 ; x = (217 - 119)/17 = 98/17
x = 98/17 ≈ 5.76
y = 7/17 ≈ 0.41
