How do you solve the system of equations $x- 4y = - 18$ and $2x + y = - 9$ ?

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Answer 1 · 2018-01-30T11:59:05

$x=-6 and y=3$

Multiply the first equation by $-2$

$-2x+8y=36$

Add this equation to the second one. Thus

$9y=27$

So

$y = 3$

Replace $y$ in the first equation:

$x - 12 = -18$

Thus

$x = -6$

How do you solve the system of equations x- 4y = - 18x- 4y = - 18 and 2x + y = - 92x + y = - 9?