How do you solve $x = 7 y + 7$ $x=7y+7$ and $- 4 x + 4 y = - 16$ $-4x+4y=-16$ ?

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How do you solve $x = 7 y + 7$ $x=7y+7$ and $- 4 x + 4 y = - 16$ $-4x+4y=-16$ ?

1 Answer

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Answer 1 · 2015-07-03T14:43:55

I found:
$x = \frac{7}{2}$ $x=7/2$
$y = - \frac{1}{2}$ $y=-1/2$

Explanation:

You can substitute for $x$ $x$ the first equation into the second to get:
$- 4 (7 y + 7) + 4 y = - 16$ $-4(7y+7)+4y=-16$
$- 28 y - 28 + 4 y = - 16$ $-28y-28+4y=-16$
$- 24 y = 12$ $-24y=12$
$y = \frac{12}{- 24} = - \frac{1}{2}$ $y=12/-24=-1/2$
now substitute back into the first equation:
$x = 7 (- \frac{1}{2}) + 7$ $x=7(-1/2)+7$
$x = \frac{7}{2}$ $x=7/2$

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How do you solve $x = 7 y + 7$ $x=7y+7$ and $- 4 x + 4 y = - 16$ $-4x+4y=-16$ ?

1 Answer

Explanation:

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How do you solve x=7y+7x=7y+7x=7y+7 and -4x+4y=-16−4x+4y=−16-4x+4y=-16?

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Explanation:

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How do you solve $x = 7 y + 7$ $x=7y+7$ and $- 4 x + 4 y = - 16$ $-4x+4y=-16$ ?