How do you solve the system?: $X+Y= -1, Y=3X-17$

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Answer 1 · 2018-03-02T06:47:04

$X=4, Y=-5$

If we know $Y=3X-17,$ we can just go ahead and replace $Y$ in $X+Y=-1$ with $3X-17$

$X+Y=-1hArrX+3X-17=-1$

Now, we have an equation with one unknown variable, which can be easily solved.

$4X-17=-1$

$4X=-1+17=16$

$X=16/4=4$

We need $Y.$ We know $X=4,$ so we can plug in $4$ for $X$ in $X+Y=-1$ and solve for $Y:$

$4+Y=-1$

$Y=-1-4=-5$

How do you solve the system?: X+Y= -1, Y=3X-17X+Y= -1, Y=3X-17