# How do you solve the following system?:  7y=4- 2x , 2x – y = -4

Jan 2, 2016

To solve, rearrange one equation so that one variable is the subject, then substitute that equation into the other equation, and solve from there.

#### Explanation:

Example method for this question would be:
$\left(1\right)$ $7 y = 4 - 2 x$
$\left(2\right)$ $2 x - y = - 4$
rearrange $\left(2\right)$ to give:
$\left(3\right)$ $2 x = y - 4$
substitute $\left(3\right)$ into $\left(1\right)$:
$7 y = 4 - \left(y - 4\right)$
$8 y = 8$
$y = 1$
Then substitute $y = 1$ into $\left(2\right)$
$2 x - 1 = - 4$
$2 x = - 3$
$x = - \frac{3}{2}$

Check by substituting both into $\left(1\right)$.
$7 = 4 + 3$