# How do you solve the following system: 5x + 8y = -2, 3x - 4y = -10?

May 10, 2016

$x = - 2 \mathmr{and} y = 1$

#### Explanation:

For the elimination method. the coefficients of one of the variable should be the same. It is fantastically easier if they can become additive inverses - same number, different signs. +5 and - 5 add to 0.

$\text{ "5x + 8y = -2 ..................." equ A}$
$\text{ " 3x - 4y = -10....................."equ B}$
$B \times 2 : \text{ "6x - 8y = -20 .................... "equ C}$

$A + B : \text{ " 11x " } = - 22$
$\text{ } x = - 2$

Substitute in A: $5 \left(- 2\right) + 8 y = - 2$ =
$\text{ } - 10 + 8 y = - 2$
$\text{ } 8 y = - 2 + 10$
$\text{ } 8 y = 8$
$\text{ } y = 1$