Answer:
Answer:
f(g(4)) = 5f(g(4))=5
Explanation:
f(x) = x² - 4x
g(x) = 2x – 3
To find f(g(4)) we must first find f(g(x))
To find f(g(x)) substitute g(x) into f(x) that's for every x in f(x) replace it with g (x)
That's
\begin{lgathered}f(g(x)) = ({2x - 3})^{2} - 4(2x - 3) \\ = 4x^{2} - 12x + 9 - 8x + 12 \\ = 4 {x}^{2} - 12x - 8x + 9 + 12\end{lgathered}
f(g(x))=(2x−3)
2
−4(2x−3)
=4x
2
−12x+9−8x+12
=4x
2
−12x−8x+9+12
We have
f(g(x)) = {4x}^{2} - 20x + 21f(g(x))=4x
2
−20x+21
Now to find f(g(4)) substitute the value of x that's 4 into f(g(x)) that's replace every x in f(g(x)) by 4
We have
\begin{lgathered}f(g(4)) = 4( {4})^{2} - 20(4) + 21 \\ = 4(16) - 80 + 21 \\ = 64 - 80 + 21 \\ = 85 - 80\end{lgathered}
f(g(4))=4(4)
2
−20(4)+21
=4(16)−80+21
=64−80+21
=85−80
We have the final answer as
f(g(4)) = 5f(g(4))=5
Hope this helps you