# How do you solve the system of equations -8x + 12y = 4 and - 10x - 2y = 22?

Apr 21, 2018

You need to use simultaneous equations.

#### Explanation:

I prefer substitution but other ways will work. Take one of the equations and solve for either x or y. Then substitute the value for x or y into the second equation.

e.g.
$x - 2 y = 7$ and $2 x + 7 y = - 8$

$x - 2 y = 7$ Solve for x
$x = 7 + 2 y$ Sub this into equation 2

$2 \left(7 + 2 y\right) + 7 y = - 8$ Solve for y
$14 + 4 y + 7 y = - 8$
$11 y = - 22$
$y = - 2$

From above
$x = 7 + 2 y$ (we now know y = -2)
$x = 7 + 2 \left(- 2\right)$
$x = 3$