Answer:
x = -3
y = -6
Step-by-step explanation:
[tex]y = 6 + 4x \\ - 5x - (6 + 4x) = 21 \\ - 9x - 6 = 21 \\ - 9x = 27 \\ x = - 3 \\ y = 6 + (4 \times - 3) = - 6[/tex]
