# How do you solve X for the following equations 2x+5y=10, y=-x-1?

Nov 29, 2016

$x = - 5$

#### Explanation:

$2 x + 5 y = 10$
$y = - x - 1$

In the first equation, substitute $y$ with $\left(- x - 1\right)$.

$2 x + 5 \left(- x - 1\right) = 10$

Open the brackets. The multiplication of negative positive yields a negative.

$2 x - 5 x - 5 = 10$

$- 3 x - 5 = 10$

Add $5$ to each side.

$- 3 x = 15$

Divide each side by $3$.

$- x = 5$ or $x = - 5$