Question

Solve the simultaneous equations by substitution method.

$-x+2y=0;10x+15y=105$

Answer 1

$-x+2y=0$ ......................(1)
$10x+15y=105$ .............(2)
Multiplying (1) by 10 we get,
$-10x+20y=0$.........(3)
Adding (2) and (3) we get,
$y=3$
Substituting $y=3$ in (1) we get,
$x=6$