How do you solve by substitution $y = 2x + 4$ and $y = 3x$ ?

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Answer 1 · 2015-06-10T19:54:57

$x=4$
$y=12$

$y=3x$ is already solved for $y$ . Substitute it into the other equation.

$y=2x+4$ =

Substitute $3x$ for $y$ and solve for $x$ .

$3x=2x+4$ =

$x=4$

Substitute $4$ for $x$ in the equation $y=3x$ .

$y=3(4)$ =

$y=12$

Check by substituting the values for $x$ and $y$ into both equations.

First equation.

$y=2x+4$ =

$12=2(4)+4$ =

$12=12$ Check.

Second equation.

$y=3x$ =

$12=3(4)$ =

$12=12$ Check.

How do you solve by substitution y = 2x + 4y = 2x + 4 and y = 3x y = 3x ?