Substitute on equation into another to find x and y y=2x+6 y=1/2x-6?

You can substitute the expression for y given by the first equation into the second equation.

  2x + 6 = y = 1/2x - 6

  4x + 12 = x - 12    (multiply by 2)

  3x + 12 = -12    (subtract x)

  3x = -24    (subtract 12)

  x = -8    (divide by 3)

  y = 2(-8) + 6    (substitute for x in the first equation)

  y = -16 + 6    (do the multiplication)

  y = -10    (do the addition)

The solution is (x, y) = (-8, -10).