Question

-4х + 7y = 20
у = 3х + 15
х —
у —​

Answer 1

Respuesta:

$-4х + 7y = 20 \\ у = 3х + 15 \\ - 4x + 7(3x + 15) = 20 \\ - 4x + 21x + 105 = 20 \\ 17x = 20 - 105 \\ 17x = - 85 \\ x = \frac{ - 85}{17} \\ x = - 5 \\ y = 3(-5) + 7 \\ y = - 15 + 7 \\ y = - 8$