SOLUTION: Please solve this system using substitution. 4x-y=5 4x+4y=-4 Thank you,

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Question 1057063: Please solve this system using substitution.
4x-y=5
4x+4y=-4
Thank you,
Answer by math_helper(2461) About Me  (Show Source):
You can put this solution on YOUR website!
4x-y = 5 (eq 1)
4x+4y = -4 (eq 2)
From (eq 1): y=4x-5
Substitute this expression for 'y' in eq 2:
4x+4(4x-5) = -4
4x+16x-20 = -4
20x = 16
x = 16/20 = 4/5, y = 4(4/5) - 5 = -9/5
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Ans: x = 4/5, y = -9/5
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Check:
(eq1) 4x-y = 4(4/5)-(-9/5) = 25/5 = 5 (ok)
(eq2) 4x+4y = 4(4/5) + 4(-9/5) = 16/5-36/5 = -20/5 = -4 (ok)