Question

Given the function f(x) = 3lx - 21+ 6, for what values of x is f(x) = 18?

A) x = 3
B) x = 5
C) x = 6
D) x = 7

Answer 1

To find the values of x for which f(x) = 18, substitute 18 for f(x) in the given function and solve for x. The values of x for which f(x) = 18 are x = 25 and x = 17.

Step-by-step explanation:

To find the values of x for which f(x) = 18, we can substitute 18 for f(x) in the given function and solve for x:

18 = 3|x - 21| + 6

12 = 3|x - 21|

4 = |x - 21|

Since the absolute value of a number is always positive, the equation |x - 21| = 4 has two solutions:

x - 21 = 4 or x - 21 = -4

x = 25 or x = 17

Therefore, the values of x for which f(x) = 18 are x = 25 and x = 17. None of the given options A) x = 3, B) x = 5, C) x = 6, D) x = 7 are correct.