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I need help to find the indicated operation:f(a)= a-4g(a)= a^3+3Find (f×g)(0)

1 Answer

1 vote

You have this function:


f\mleft(a\mright)=a-4

And the other function is:


g\mleft(a\mright)=a^3+3

So, to find


\mleft(f\cdot g\mright)(a)

You need to multiply both functions, as you can see below:


\begin{gathered} (f\cdot g)(a)=(a-4)(a^3+3) \\ (f\cdot g)(a)=(a)(a^3)+(a)(3)+(-4)(a^3)+(-4)(3) \\ (f\cdot g)(a)=a^4+3a-4a^3-12 \\ (f\cdot g)(a)=a^4-4a^3+3a-12 \end{gathered}

Now, to find


(f\cdot g)(0)

You need to substitute this value and evaluate:


a=0

Then, you get:


\begin{gathered} (f\cdot g)(0)=(0)^4-4(0)^3+3(0)-12 \\ (f\cdot g)(0)=-12 \end{gathered}

The answer is:


(f\cdot g)(0)=-12