Question

Solve and show steps -2x+y=-7 and -2x-4y=-12

Answer 1

Answer:

  (x, y) = (4, 1)

Step-by-step explanation:

The coefficients of x are the same, so we can cancel the x-terms by subtracting one equation from the other. We want to do this so the resulting y-coefficient will be positive. That means we want to subtract the second equation from the first:

  (-2x +y) -(-2x -4y) = (-7) -(-12)

  5y = 5 . . . . . . . . simplify

  y = 1 . . . . . . . . divide by 5

  -2x +1 = -7 . . . . . substitute for y in the first equation

  -2x = -8 . . . . . subtract 1

  x = 4 . . . . . . divide by -2

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

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A graphing calculator easily verifies the solution.