Unit 3, Lesson 3 Mrs. King

 Function rule: an equation that describes a function.  Function notation: when you use f(x) = instead of y =.

A function may be evaluated at different values of x by substituting the x-values into the function. For example, to evaluate the function defined by f (x)=2x at x=5; The names of functions are given by either lowercase or uppercase letters.

x8 – 3xf(x)f(x) 18 – 3(1)5 28 – 3(2)2 38 – 3(3) 48 – 3(4)-4

Make a table for ƒ(t) = 0.5t + 1. Use 1, 2, 3, and 4 as domain values. t0.5t + 1f(t)f(t) 10.5(1) (2) (3) (4) + 13

Evaluate the function rule ƒ(g) = –2g + 4 to find the range for the domain {–1, 3, 5}. The range is {–6, –2, 6}. ƒ(g) = –2g + 4 ƒ(5) = –2(5) + 4 ƒ(5) = –6 ƒ(g) = –2g + 4 ƒ(–1) = –2(–1) + 4 ƒ(–1) = 6 ƒ(g) = –2g + 4 ƒ(3) = –2(3) + 4 ƒ(3) = –2

Find the range of the function ƒ(g) = 3g – 5 for the domain {–1.5, 2, 4}. {–9.5, 1, 7}