There are 2 methods you are taught in Middle School.
Elimination and Substitution.
Im guessing that it is 5 but then again dont trust me XD
The discontinuity occurs when the denominator is equal to zero, as it has "infinite" slope, and thus is not a real value or point.
x^2+x-12
x^2+4x-3x-12
x(x+4)-3(x+4)
(x-3)(x+4)
So discontinuities occur when x=-4 and x=3
