[mrollins2]

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]

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?