# How do you solve x+2y=4 and 3x-4y=7?

Apr 1, 2016

Solving by substitution:

#### Explanation:

$x + 2 y = 4 \to x = 4 - 2 y$

$3 \left(4 - 2 y\right) - 4 y = 7$

$12 - 6 y - 4 y = 7$

$- 10 y = 7 - 12$

$- 10 y = - 5$

$y = \frac{1}{2}$

$x + 2 \left(\frac{1}{2}\right) = 4$

$x + 1 = 4$

$x = 3$

Your solution set is $\left\{3 , \frac{1}{2}\right\}$. Don't forget to present your solutions in the form $\left\{x , y\right\}$.

Hopefully this helps!