Răspuns:
Explicație pas cu pas:
4x +20y = 240
5(10-x) = 4-y
4x +20y = 240
50-5x+y = 4
4x +20y = 240
-5x +y = -46 |*-20
4x + 20y = 240
100x -20y = 920 le adunam
104x + 0 = 1160
x = 1160/104 = 145/13
-5*145/13 + y = -46*13
-5*145 + 13y = -46*13
-725 +13y = -598
13y = 127
y = 127/13