How do you solve 2x-5y=-19 and 3x+2y =0?

Apr 24, 2018

$y = 3$ and $x = - 2$

Explanation:

There are multiple ways to solve simultaneous equations. You can use an "elimination" method, where you remove one of the unknown from the equation or use a "substitution" method. I will use a substitution method, where you substitute one variable with an expression containing the other value.

if

$3 x + 2 y = 0$

then

$y = \left(\frac{- 3 x}{2}\right)$

Substitute this value for $y$ into the other equation:

$2 x - 5 y = - 19$

$2 x - 5 \left(\frac{- 3 x}{2}\right) = - 19$

$2 x + \frac{15 x}{2} = - 19$

$4 x + 15 x = - 38$

$19 x = - 39$

$x = - 2$

So, using any of the two equations we can find $y$:

$2 \left(- 2\right) - 5 y = - 19$

$- 4 - 5 y = - 19$

$- 5 y = - 15$

$y = 3$