Question 174765
Multiply, and then evaluate for X = 4: 
9x^2-25 
-------
X+3 
times 
X^2+3X
----------
3X^2+4X-15
+++++++++++++++++++++++++++
={{{(9x^2-25)*(x^2+3x)/((x+3)*(3x^2+4x+15))}}}
={{{(9x^2-25)*x*(x+3)/((x+3)*(3x^2+4x+15))}}}
Cancel (x+3)
={{{(9x^2-25)*x/(3x^2+4x+15)}}}
={{{x*(3x-5)*(3x+5)/(3x^2+4x+15)}}}
={{{x*(3x-5)*(3x+5)/(3x^2+4x+15)}}}
That's all you can do.
@x=4:
=(4*7*17)/(48+16+15)
=476/79
-----------
If there's a typo, and it should be: -15 instead of +15
={{{x*(3x-5)*(3x+5)/(3x^2+4x-15)}}}, then
={{{x*(3x-5)*(3x+5)/((3x-5)*(x+3))}}}
={{{x*(3x+5)/((x+3))}}}
and @x=4:
= 4*17/7
= 76/7