SOLUTION: If f(x) = 6x + 7 and g(x) = x² - 4, find each value. 1.) f(-3) 2.) f(m) 3.) f(r-2) 4.) g(5) 5.) g(a) + 9 How do I solve?

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Question 1121271: If f(x) = 6x + 7 and g(x) = x² - 4, find each value.
1.) f(-3)
2.) f(m)
3.) f(r-2)
4.) g(5)
5.) g(a) + 9
How do I solve?
Answer by Edwin McCravy(20056)   (Show Source): You can put this solution on YOUR website!
Just substitute for x whatever is in the parentheses after f or g,
then simplify.

If f(x) = 6x + 7 and g(x) = x² - 4, find each value. 

1.) f(-3) 
Substitute (-3) for x in f(x) = 6x + 7
                        f(-3) = 6(-3) + 7
                        f(-3) = -18 + 7
                        f(-3) = -11 

2.) f(m)
Substitute (m) for x in f(x) = 6x + 7
                        f(m) = 6(m) + 7
                        f(m) = 6m + 7
                         
3.) f(r-2)
Substitute (r-2) for x in f(x) = 6x + 7
                        f(r-2) = 6(r-2) + 7
                        f(r-2) = 6r - 12 + 7
                        f(r-2) = 6r - 5  


4.) g(5)
Substitute (5) for x in g(x) = x² - 4
                        g(5) = (5)² - 4
                        g(5) = 25 - 4
                        g(5) = 21 

5.) g(a) + 9
Substitute (a) for x in g(x) = x² - 4
                        g(a) = (a)² - 4
                        g(a) = a² - 4

Then add +9 to both sides:

                    g(a) + 9 = a² - 4 + 9
                    g(a) + 9 = a² + 5

Edwin
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