Question

Solve the following system of equations by linear combination: 3x+2y=7 y=x-4

Answer 1

Answer : (3,-1) Hoped this helped :)

Answer 2

$\left \{ {{3x+2y=7} \atop {y=x-4}} \right.$

Express $y$ from first equation:
$2y=7-3x$
$y=\frac{7-3x}{2}$

Then, replace $y$ in second equation with found value and solve it:
$\frac{7-3x}{2}=x-4$
$7-3x=2x-8$
$5x=15$
$x=15/5=3$

Now, replace $x$ in first equation with found value and solve it too:
$3*3+2y=7$
$9+2y=7$
$2y=-2$
$y=-2/2=-1$

So the result is: $x=3$ and $y=-1$