How do you simplify #(4x^2+2x-1 )/( x+3 )#?
By factoring the numerator of your function!
In order to factor it, we must find its roots, which are
Now, we have
P.s.: I adopted
If, by "simplify" you mean "remove common factors" (or "reduce the fraction"), the expression is already as simple as it will get.
It cannot be further simplified.