p(x)+p(5), if p(r)=4r^2+5

Question

p(x)+p(5), if p(r)=4r^2+5 I do not understand how to do this question I have read over the chapter and I still don't understand how to do this function.

Answer 1

This is a question about how to add two functions together. The way you solve these types of problems, is to first substitute the given variables into the function, and then perform the addition.

Given that p(r) = 4r^2 + 5,

you can start by substituting the variables given in your problem in to the function.

 

First, substitute x for r in p(r)

 

p(x) = 4x^2 + 5,

 

Second, substitute 5 for r in p(r)

 

p(5) = 4*5^2 + 5 = 4*25 + 5 = 100 + 5 = 105.

 

Next, add p(x) to p(r), and simplify

 

[4x^2 + 5] + [4*5^2 + 5]

[4x^2 + 5] + [105] as shown above

[4x^2 + 5 + 105 = 4x^2 + 110.

 

The answer is 4x^2 + 110.

 

I hope you understand. If you need any more clarification, or to solve any more problems, feel free to contact me.