Let f(x) = x + 5. What is f(x^2 + 3)?

Question

How do you solve this?

 

I came up with x^2 + 10x + 28, and I'm not sure if it's correct.

Answer 1

If f(x) = x + 5, then to find f(x²+3), just replace x by x²+3.

 

So, f(x²+3) = (x²+3)+5 = x²+8