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If f(x) = 3 + 5x and g(x) = 2x2 – 4, find (f + g)(x).

If f(x) = 3 + 5x and g(x) = 2x2 – 4, find (f + g)(x).-example-1
User MichelleJS
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1 Answer

4 votes

Given the functions:


\begin{gathered} f(x)=3+5x \\ g(x)=2x^2-4 \end{gathered}

You need to add them, in order to find:


(f+g)(x)

Then, you have to set up:


(f+g)(x)=(3+5x)+(2x^2-4)

It is important to remember the Sign Rules for Multiplication:


\begin{gathered} +\cdot+=+ \\ -\cdot-=+ \\ -\cdot+=- \\ +\cdot-=- \end{gathered}

Then:


(f+g)(x)=3+5x+2x^2-4

By adding the like terms (these are defined as those terms that have the same variables with the same exponents), you get:


(f+g)(x)=2x^2+5x-1

Hence, the answer is: First option.

User Joyal
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