(04.01)solve the following system of equations by substitution and select the correct answer below: 4x − 6y = 28 8x − 4y = 24

It is convenient to divide the second equation by 2, then substitute for 4x in the first equation.
  4x -2y = 12
  4x = 12 + 2y . . . . solve for 4x

  (12 +2y) -6y = 28 . . . . substitute for 4x
  -4y = 16 . . . . . . . . . . . . subtract 12
  y = -4 . . . . . . . . . . . . . .divide by -4

  4x = 12 + 2(-4) = 4
  x = 1

The solution is (x, y) = (1, -4).