# How do you solve 3x+y=4 and 2x+y=1?

Apr 4, 2018

$\left(3 , - 5\right)$

#### Explanation:

I used substitution.

Isolate $y$ in one of the equations.
$3 x + y = 4$
$y = 4 - 3 x$

Substitute $y$ in $2 x + y = 1$ for $4 - 3 x$.
$2 x + \left(4 - 3 x\right) = 1$
$2 x + 4 - 3 x = 1$
$4 - x = 1$
$- x = - 3$
$x = 3$

Substitute $x$ back into $y = 4 - 3 x$ find the value of $y$.
$y = 4 - 3 \left(3\right)$
$y = 4 - 9$
$y = - 5$

Answer (Coordinate Form): $\left(3 , - 5\right)$