Can someone help me this is my last question?

Answer: Let's solve for f.
fx=
7−x2
5+x2
Step 1: Multiply both sides by x^2+5.
fx3+5fx=−x2+7
Step 2: Factor out variable f.
f(x3+5x)=−x2+7
Step 3: Divide both sides by x^3+5x.
f(x3+5x)
x3+5x
=
−x2+7
x3+5x
f=
−x2+7
x3+5x
Answer:
f=
−x2+7
x3+5x