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Question 107388: Find the following if f(x) = 5x -1 f(a-2)
a-2 = 5(a-2) - 1
a-2 = 5a -10 - 1
-2 = -4
1 = 2
Double checking to see if I did these right
Answer by bucky(2189)   (Show Source):
You can put this solution on YOUR website! You are having a little trouble with the left side of the equation. Here's the way to do this
type of problem:
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Given:
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f(x) = 5x - 1
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To find f(a-2) all you do is to plug (a-2) in for every x in the given equation. When you
make that substitution the given equation becomes:
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f(a-2) = 5(a-2) - 1 <=== note the difference in the left side compared to yours
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Then multiply out the right side, just as you did, and the equation becomes:
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f(a-2) = 5a - 10 - 1
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Finally combine the -10 and the -1 to get - 11 and the equation becomes:
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f(a-2) = 5a - 11
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That's the answer. You were asked to find f(a-2) and you did. It equals 5a - 11.
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Hope this helps you to see where you went astray. The left side of the equation never really
gets involved with solving the right side. It just stays f(a-2).
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