 # Solving a system of equations by adding or subtracting.

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Solving a system of equations by adding or subtracting

2x + 3y = 11 -2x + 5y = 13 When using the adding or subtracting method, one of the variable combinations can completely eliminate themselves if you were to combine the 2 equations together In this example, the X’s can Eliminate themselves 8y = 24 88 y = 3 What we know now is that the answer will be (?, 3) To find the value of x you Use either equation from The question and substitute In to find your answer 2x + 3(3) = 11 2x + 9 = 11 -9 2x = 2 22 x = 1 The Answer Is (1, 3)

4x + 3y = 2 5x + 3y = -2 When using the adding or subtracting method, one of the variable combinations can completely eliminate themselves if you were to combine the 2 equations together In this example, the Y’s can eliminate themselves If we do 1 thing first -1x = 4 x = -4 What we know now is that the answer will be (-4, ?) To find the value of y you Use either equation from The question and substitute In to find your answer 4(-4) + 3y = 2 -16 + 3y = 2 +16 3y = 18 33 y = 6 The Answer Is (-4, 6) -5x – 3y = 2

8x – 4y = -4 4y = 3x + 14 In this example, we need for both equations to be in the same form. I am going to put the bottom equation into standard form to solve. 5x = 10 55 x = 2 What we know now is that the answer will be (2, ?) To find the value of y you Use either equation from The question and substitute In to find your answer 8(2) - 4y = -4 16 - 4y = -4 -16 -4y = -20 -4 y = 5 The Answer Is (2, 5) -3x + 4y = 14

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