Lesson 23
Comparing Functions
- Let’s evaluate and compare functions.
23.1: Math Talk: Evaluating Functions
Mentally evaluate each of the functions when \(x = 3\).
\(f(x) = x^2 - 4x + 1\)
\(g(x) = 6x - 2x^2\)
\(h(x) = (x-4)(x-3)\)
\(j(x) = 2(x-1)(x+2)\)
23.2: Comparing Functions
The notation \(f(2)\) means the output of function \(f\) when \(x\) is 2. For each function, determine whether \(f(2) > f(3)\), \(f(2) < f(3)\), or \(f(2) = f(3)\).
- \(f(x) = x^2 + 2x+ 3\)
- \(f(x) = (x-2)(x-3)\)
- \(f(x) = \text{-}x^2 + 5\)
23.3: Finding the Vertex
Write each function in vertex form, then find the coordinates of the vertex.
- \(y = x^2 - 4x + 7\)
- \(y = (x-1)(x+3)\)
- \(y = (x-2)(x+2)\)
- \(y = x^2 - 2x + 1\)
- \(y = \text{-}x^2 -2x-6\)
- \(y = 2x^2 - 12x + 22\)