# How do solve the following linear system?: 9x + 1 = -4y, 7x - 2y - 13 = 0 ?

Mar 5, 2018

$\textcolor{b l u e}{x = - \frac{62}{5}} , \textcolor{g r e e n}{y = \frac{27}{5}}$

#### Explanation:

$9 x + 1 = - 4 y$ Eqn (1)

$y = \frac{9 x + 1}{-} 4$

$7 x - 2 y = 13$ Eqn (2)

Substituting value of yin Eqn (2),

$7 x - \left(2 \cdot \frac{9 x + 1}{-} 4\right) = 13$

$- 28 x + 18 x + 2 = - 52$

$- 10 x = - 54$ or $x = \frac{27}{5}$

Substituting value of x in Eqn (1),

$y = \frac{9 \cdot \left(\frac{27}{5}\right) + 1}{-} 4 = \frac{243 + 5}{-} 20 = - \frac{62}{5}$