# How do you solve 15x-20y=-1 and 10y=1+5x using substitution?

Aug 3, 2016

$x = \frac{1}{5}$
$y = \frac{1}{5}$

#### Explanation:

$15 x - 20 y = - 1$ or $15 x = 20 y - 1$
Multipling both sides of the equation $10 y = 1 + 5 x$ by $3$
we get
$30 y = 3 + 15 x$
or
$15 x = 30 y - 3$ And we have $15 x = 20 y - 1$
$30 y - 3 = 20 y - 1$
or
$30 y - 20 y = 3 - 1$
or
$10 y = 2$
or
$y = \frac{2}{10}$
or
$y = \frac{1}{5}$===============Ans $1$
We have $15 x = 20 y - 1$
so
$15 x = \frac{20}{5} - 1$
or
$15 x = 4 - 1$
or
$15 x = 3$
or
$x = \frac{3}{15}$
or
$x = \frac{1}{5}$================Ans$2$