Question 70358
If f(x)= 4x -3, find the following:

f(-1)

What f(-1) tells you to do is to start with f(x) = 4x - 3, then replace every x you see
in it by (-1), and finally compute what the right side equals.
.
Let's change the problem a little and find f(-4).  Go to the expression f(x) = 4x - 3 and 
replace all the x's by -4.  When you do the expression becomes:
.
f(-4) = 4(-4) - 3
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When you multiply 4 times -4 you get -16.  Substitute -16 for 4(-4) and the expression
becomes
.
f(-4) = -16 -3 and the two terms on the right combine so that the expression becomes:
.
f(-4) = -19
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You can do the work to find f(-1).  Follow the same process as the example.
.
I hope this helps you to understand what the problem really means.