Question

8.7 use radicals in functions (homework)
score: 3/10 answered: 4/10
question 5
if $f(x)=sqrt{15 - 5x}$, then $f(-4)=$ (leave your answer in exact form. enter dne if the function is undefined or not a real number)
question help: video written example
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Explanation:

Step1: Substitute x = - 4

Substitute \(x=-4\) into \(f(x)=\sqrt{15 - 5x}\), we get \(f(-4)=\sqrt{15-5\times(-4)}\).

Step2: Calculate the value inside the square - root

First, calculate \(15-5\times(-4)=15 + 20=35\). So \(f(-4)=\sqrt{35}\).

Answer:

\(\sqrt{35}\)