If f(x) = 4 – x2 and g(x) = 6x, which expression is equivalent to (g – f)(3)?
f(x) = -x² + 4
g(x) = 6x
(g - f)(3) = 6(3) - (-(3)² + 4)
(g - f)(3) = 18 - (-9 + 4)
(g - f)(3) = 18 - (-5)
(g - f)(3) = 18 + 5
(g - f)(3) = 23
For this case we have the following functions:
\(f (x) = 4 - x ^ 2
g (x) = 6x
\)
The first thing we must do for this case is to subtract both functions.
We have then:
\((g - f) (x) = g (x) - f (x)
\)
Substituting we have:
\((g - f) (x) = (6x) - (4 - x ^ 2)
\)
Rewriting we have:
\((g - f) (x) = x ^ 2 + 6x - 4
\)
Evaluating the obtained function for x = 3 we have:
\((g - f) (3) = (3) ^ 2 + 6 (3) - 4
(g - f) (3) = 23
\)
Answer:
The value of the function evaluated at x = 3 is:
\((g - f) (3) = 23\)