mrollins2
Aug 29, 2012, 11:27 AM
using the functions defined below, determine the indicated values.
 
 
f(x)=3-10x     g(x)=x^2-x+9
 
g(-2)
 
 
 
f(7)-g(-2)
 
 
g(3) . f(2)
 
 
I know the answers but I have no idea how to get to them
ebaines
Aug 29, 2012, 02:15 PM
Think of a function as a machine which takes an input, does some manipulation on it, and spits out an output.  So for example if you have a function defined as:
 
h(x) = 3x+6
 
you stick in a value for x of, say, 2, and get the output of 3(2)+6 = 6+6 = 12.  You would write this as: h(2) = 3(2) + 6.
 
Let's try one of the functions you have to work with: g(x) = x^2 -x + 9.  If you input x = 1 you get output g(1) = 1^2-1+9 = 9.  For x= 2 you get g(2)=2^2-2+9 = 11.  For x = -10 you get g(-10)=(-10)^2-(-10)+9 = 119. See how it works?