# How do you solve 7x-2y=8 and 5x+2y=4 using substitution?

May 7, 2018

Find $2 y$ in the first and put the value in the second equation

#### Explanation:

$7 x - 8 = 2 y$ after arranging the first original equation. Put this into the second

$5 x + 2 y = 4$

$5 x + 7 x - 8 = 4$

$12 x = 4 + 8$

$x = \frac{12}{12} = 1$

Now find y.

$2 y = 7 x - 8$

$2 y = 7 - 8$

$2 y = - 1$

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

Your answer is $x = 1$ and $y = - \frac{1}{2}$