1) rewrite x^2-9 in the form a^2-b^2, where a=x and b=3.
4 over x+3 + 3 over x^2-3^2
2)Use difference of squares
4 over x+3 + 3 over (x+3)(x-3)
3) Cross multiply
4(x-3)+3 over (x+3)(x-3)
4) Expand
4x-12+3 over (x+3)(x-3)
5) Simplify 4x-12+34x−12+3 to 4x-94x−9
4x-9 over (x+3)(x-3)