SOLUTION: Evaluate the piecewise function at the given value of the independent variable. f(x)= -5x-2 if <4 -2x-4 if > 4 Determinre f(7)

Algebra ->  Equations -> SOLUTION: Evaluate the piecewise function at the given value of the independent variable. f(x)= -5x-2 if <4 -2x-4 if > 4 Determinre f(7)       Log On


   



Question 1135782: Evaluate the piecewise function at the given value of the independent variable.


f(x)= -5x-2 if <4
-2x-4 if > 4 Determinre f(7)
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Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!

Answer: -18
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How I got that answer:

The piece wise function f(x) has a dual identity so to speak. It is either f%28x%29+=+-5x-2 OR f%28x%29+=+-2x-4. It depends on what the x value is. Note: f(x) cannot be both at the same time.

If x+%3C+4, then f%28x%29+=+-5x-2 as the first line shows in the piecewise function.
OR
If x+%3E=+4, then f%28x%29+=+-2x-4 as the second line shows in the piecewise function.

The value x = 7 makes x+%3E=+4 a true inequality. This value is larger than 4. So we will use f%28x%29+=+-2x-4 as our function

Plug in x = 7. Use the order of operations PEMDAS to simplify
f%28x%29+=+-2x-4
f%287%29+=+-2%287%29-4 Replace every x with 7
f%287%29+=+-14-4
f%287%29+=+-18