Answer:
a. f(12) = - 1
b. x = 27 when f(x) = 4
Step-by-step explanation:
We are given that [tex]f(x)=\frac{1}{3} x-5[/tex] and we want to find f(12) and f(x) = 4
To find f(12) we simply plug in 12 into x and evaluate it
[tex]f(x)=\frac{1}{3} x-5[/tex]
plug in 12
[tex]f(12)=\frac{1}{3} (12)-5[/tex]
multiply 12 and 1/3 to get 4
[tex]f(12)=4-5[/tex]
subtract 5 from 4 to get -1
[tex]f(12)=-1[/tex]
Now we want to find the value of x when f(x) = 4
To do this we substitute 4 for f(x) and solve for x
[tex]f(x)=\frac{1}{3} x-5[/tex]
substitute 4 for f(x) and solve for x
[tex]4=\frac{1}{3}x -5[/tex]
add 5 to both sides
[tex]9=\frac{1}{3} x[/tex]
multiply both sides by 3
27 = x
And we are done.
So f(12) = -1 and x = 27 when f(x) = 4
