Question

-4x-(x-5y) якщо y-x=-2

Answer 1

$y-x=-2 \\ \\ x=y+2\\ \\ -4x-(x-5y)=-4x-x+5y = -4\cdot (y+2)-(y+2)+5y =-4y-8-y-2+5y=\\ \\ =-10$