Question

Solve the following systems of equations by using the method of substitution:
$x+2y=-1$
$2x-3y=12$

Answer 1

The given system of equations is
$x+2y=-1$ (i)
$2x-3y=12$ .(ii)

From equation (i), we get
$x=-1-2y$

Substituting $x=-1-2y$ in equation (ii), we get

$\Rightarrow 2(-1-2y)-3y=12$
$\Rightarrow -2-4y-3y=12$

$\Rightarrow -7y=14$
$\Rightarrow y=-2$

Putting $y=-2$ in $x=-1-2y$, we get
$x=-1-2\times (-2)=3$

Hence, the solution of the given system of equations is $x=3,y=-2$.