How do you solve the following linear system:  y = - 3x - 3, 4x-5y=18 ?

Nov 15, 2015

Solution Set$= \left(x , y\right) = \left(\frac{3}{19} , - \frac{66}{19}\right)$

Explanation:

Adding $3 x$ to both sides of 1st equation
$3 x + y = - 3$

Multiplying both sides of above equation by $5$
$15 x + 5 y = - 15$

Adding above equation to 2nd equation of question
$19 x = 3$
$x = \frac{3}{19}$

Subsituting value of x in 1st equation of question
$y = - 3 \left(\frac{3}{19}\right) - 3$
$y = - \frac{9}{19} - 3$
$y = \frac{- 9 - 57}{19}$
$y = - \frac{66}{19}$