Answer :
20x - 30y = -50 ⇒ 20x - 30y = -50
x + 2y = -1 ⇒ 20x + 40y = -20
-70y = -30
-70 -70
y = ³/₇
20x - 30(³/₇) = -50
20x - 12⁶/₇ = -50
+ 12⁶/₇ + 12⁶/₇
20x = 47¹/₇
20 20
x = 2⁷/₂₀
(x, y) = (2⁷/₂₀, ³/₇)
x + 2y = -1 ⇒ 20x + 40y = -20
-70y = -30
-70 -70
y = ³/₇
20x - 30(³/₇) = -50
20x - 12⁶/₇ = -50
+ 12⁶/₇ + 12⁶/₇
20x = 47¹/₇
20 20
x = 2⁷/₂₀
(x, y) = (2⁷/₂₀, ³/₇)
