# How do you solve y= x+3 and x-4y=0  using substitution?

Aug 22, 2017

$x = - 4$

$y = - 1$

#### Explanation:

$y = x + 3 \text{ } \left(1\right)$

$x - 4 y = 0 \text{ } \left(2\right)$

Substitute the value of $y$ in equation $\left(2\right)$. We get

$x - 4 \left(x + 3\right) = 0$

$x - 4 x - 12 = 0$

$- 3 x = 12$

$x = - 4$

Substitute the value in equation $\left(1\right)$. We get

$y = - 4 + 3$

$y = - 1$