Final answer:
The critical value of the function S(x) = (4 - x)(x + 6) is found by setting its first derivative equal to zero. The derivative S'(x) = -2x - 2 when set to zero gives the critical value x = -1.
Step-by-step explanation:
To find the critical values of the function S(x) = (4 - x)(x + 6), we need to set its first derivative equal to zero and solve for x. The critical values are the x-values where the first derivative equals zero or where the derivative is undefined.
First, we'll find the derivative of S with respect to x. Applying the product rule:
S'(x) = (4-x)'(x+6) + (4-x)(x+6)'
S'(x) = (-1)(x+6) + (4-x)(1)
S'(x) = -x - 6 + 4 - x
S'(x) = -2x - 2
To find the critical values, we set S'(x) to zero:
-2x - 2 = 0
2x = -2
x = -1
Thus, the critical value of the function S(x) is x = -1.