College Algebra

Question

Given: 𝑓(𝑥)=2𝑥−1 𝑎𝑛𝑑𝑔(𝑥)= 𝑥2 +𝑥−5 𝑓𝑖𝑛𝑑(𝑔−𝑓)(3)

Answer 1

Hello, thank you for taking the time to post your question!

To find the value of (g – f)(3) you want to take g(x) – f(x) and then plug in the value x = 3.

g(x) – f(x) = x^2 + x – 5 – (2x – 1) = x^2 + x – 5 – 2x + 1 = x^2 – x – 4

then you can plug in x = 3 into that expression

(3)^2 – 3 – 4 = 9 – 3 – 4 = 2

Meaning that (g – f)(3) = 2

I hope that helps you get moving in a better direction on this type of question! Feel free to reach out if you have any additional questions beyond that :)

Answer 2

𝑓(𝑥)=2𝑥−1

𝑔(𝑥)= 𝑥² +𝑥−5

 

F𝑖𝑛𝑑(𝑔−𝑓)(3).  OK, this is pretty easy:

 

f(x) = 2x - 1

f(3) = 2·3 - 1 = 6 - 1 = 5

 

g(x) = x² + x - 5

g(3) = 3² + 3 - 5 = 9 + 3 - 5 = 7

 

(g-f)(3) = g(3) - f(3) = 7 - 5 = 2