Solve the system of equations: y - 2x = 4, 7x - y = 1

Add the two equations: (y - 2x) + (7x - y) = 4 + 1, which simplifies to 5x = 5, so x = 1.

Substitute x = 1 into the first equation: y - 2(1) = 4, so y - 2 = 4, which means y = 6.

Solution: x = 1, y = 6.