How do solve the following linear system?: $y = 4x + 4, 3x - y = -6$ ?

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Answer 1 · 2018-05-21T09:52:24

$x=2$ and $y=12$

In two linear equation system, make one variable the subject and substitute that variable in the second equation.

$y = 4x+4$ $->$ equation 1
$3x-y=-6$ $->$ equation 2

Substitute $y$ from equation 1 to equation 2:

$3x - (4x+4) = -6$

$3x-4x-4 = -6$

$-x-4 = -6$

$-x = -6+4$

$-x = -2$

$x = 2$

Substitute $x=2$ in equation 1 or equation 2 to get value of $y$ .
Lets take equation 1:

$y=4x+4$ $->$ equation 1

$y=4(2) + 4$

$y=8+4$

$y=12$

So we get $x=2$ and $y=12$

Check the answer:

$3x-y=-6$
$3(2) - 12 = -6$
$6-12=-6$
$-6=-6$ $->$ Correct

How do solve the following linear system?: y = 4x + 4, 3x - y = -6 y = 4x + 4, 3x - y = -6 ?