How do you solve by substitution $-x + 2y = -6$ and $3x + y = 8$ ?

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Answer 1 · 2018-04-29T22:44:30

$(22/7,-10/7)$

In the second equation, we can easily solve for $y$ by subtracting $3x$ from both sides. We get:

$y=8-3x$

We've already solved for one variable in terms of the other, so we can plug into the first equation. We get

$-x+2(8-3x)=-6$

$=>-x+16-6x=-6$

$=>-7x+16=-6$

We can subtract $16$ from both sides to get

$-7x=-22$

Dividing both sides by $-7$ , we get

$color(blue)(x=22/7)$

We can plug into our equation for $y$ , $y=8-3x$ . We get

$y=8-3(22/7)$

$y=56/7-66/7$

$color(lime)(y=-10/7)$

Hope this helps!

How do you solve by substitution -x + 2y = -6-x + 2y = -6 and 3x + y = 83x + y = 8?