Can someone help me solve using the substitution method? 6x-7y=-46 5x + 48 = y

The second equation gives you an expression for y that you can substitute into the first equation.
  6x - 7(5x+48) = -46
  6x - 35x - 336 = -46    (eliminate parentheses)
  -29x = 290    (add 336, collect terms)
  x = -10    (divide by -29)

  5(-10) + 48 = y    (use the second equation to find y)
  -2 = y

The solution is (x, y) = (-10, -2).
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Check
  We have used the second equation to get y, so we only need to verify our answer in the first equation.
  6(-10) - 7(-2) = -46
  -60 + 14 = -46    (yes)