How do you solve $3 x + 4 y = - 10$ $3x+4y=-10$ and $x - 4 y = 2$ $x-4y=2$ ?

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How do you solve $3 x + 4 y = - 10$ $3x+4y=-10$ and $x - 4 y = 2$ $x-4y=2$ ?

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Answer 1 · 2016-03-21T08:31:26

$x = - 2; y = - 1$ $x = -2; y = -1$

Explanation:

First solve for $x$ $x$ by adding the two equations:

$3 x + 4 y = - 10$ $3x + 4y = -10$
+ $x - 4 y = 2$ $x - 4y = 2$

This gives you:
$4 x = - 8$ $4x = -8$ , so $x = - 2$ $x = -2$

Then you can solve for $y$ $y$ by either plugging $- 2$ $-2$ in for $x$ $x$ or by multiplying the second equation by $- 3$ $-3$ and adding the two equations again:

    #3x + 4y = -10#

+ $- 3 (x - 4 y) = 2 \cdot - 3$ $-3(x - 4y) = 2*-3$

This gives:
$16 y = - 16$ $16y = -16$ , so $y = - 1$ $y = -1$

You can verify your answer by plugging $- 2$ $-2$ in for $x$ $x$ and $- 1$ $-1$ in for $y$ $y$ in both equations.

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How do you solve $3 x + 4 y = - 10$ $3x+4y=-10$ and $x - 4 y = 2$ $x-4y=2$ ?

1 Answer

Explanation:

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How do you solve $3 x + 4 y = - 10$ $3x+4y=-10$ and $x - 4 y = 2$ $x-4y=2$ ?