Question

Solve the following systems of equations graphically:
$x+y=3$
$2x+5y=12$

Answer 1

We can see in the figure that two lines intersect at a point in 1st quadrant

Multiply 1st equation on both sides by 2

$\Rightarrow 2x+2y=6$

$\Rightarrow 2x+5y=12$

Subtract two equations ;

$\Rightarrow 3y=6$

$\Rightarrow y=2$

$\Rightarrow x=3-y=3-2=1$

$\Rightarrow x=1,y=2$