How do you solve $-8x - 8y = 0$ and $-8x + 8y = -128$ ?

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Answer 1 · 2017-09-03T14:10:57

See a solution process below:

Step 1) Solve the first equation for $x$ :

$-8x - 8y = 0$

$-8x - 8y + + color(red)(8y) = 0 + color(red)(8y)$

$-8x - 0 = 8y$

$-8x = 8y$

$(-8x)/color(red)(-8) = (8y)/color(red)(-8)$

$1x = -1y$

$x = -y$

Step 2) Substitute $-y$ for $x$ in the second equation and solve for $y$ :

$-8x + 8y = -128$ becomes:

$(-8 * -y) + 8y = -128$

$8y + 8y = -128$

$16y = -128$

$(16y)/color(red)(16) = -128/color(red)(16)$

$y = -8$

Step 3) Substitute $-8$ for $y$ in the solution to the first equation at the end of Step 1 and calculate $x$ :

$x = -y$ becomes:

$x = - -8$

$x = 8$

The Solution Is: $x = 8$ and $y = -8$ or $(8, -8)$

How do you solve -8x - 8y = 0-8x - 8y = 0 and -8x + 8y = -128-8x + 8y = -128?