Question 1103262: Solve the system of equations -2x-2y=−4 and 4x+3y=11 by combining the equations Found 2 solutions by richwmiller, rothauserc:Answer by richwmiller(17219) (Show Source):
You can put this solution on YOUR website! combining the equations is also known as adding and subtracting equations as well as the elimination method.
1) -2x-2y=−4
2) 4x+3y=11
We notice that if we multiply the first equation by 2 we can then add the new equation 3) and 2) to eliminate x
3) -4x-4y=−8
2) 4x+3y=11
-y=3
y=-3
substitute -3 in 2)
4x+3y=11
4x+3(-3)=11
4x-9=11
4x=20
x=5
check in 1)
-2x-2y=−4
-2(5)-2(-3)=-4
-10+6=-4
-4=-4
ok
You can put this solution on YOUR website! 1) -2x-2y=−4
:
2) 4x+3y=11
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multiply equation 1 by 2
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3) -4x -4y = -8
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add equation 3 to equation 2
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-y = 3
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y = -3
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substitute for y in equation 1
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-2x -2(-3) = -4
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-2x +6 = -4
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-2x = -10
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x = 5
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x = 5 and y = -3
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substitute for x and y in equation 2
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4(5) +3(-3) = 11
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20 -9 = 11
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11 = 11
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our answer checks
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