DENOTING
Eqn 1: 3x+4y=58
Eqn 2: 1x+3y=36
TRANSLATING
(Multiply Eqn 2 by 3)
Eqn 3: 3x+9y=108
ELIMINATION
(Subtract Eqn 3 from Eqn 2)
Eqn 4: -5y=-50
Divide both sides by -5 to derive the value of y.
y=10
SUBSTITUTION
(Substitute the value of y to any of the first two equations)
3x+4(3)=58
3x=58-12
3x=46
x=46/3 or 15 1/3