Question

Determine which ordered pairs fall on the graph of f(x) = -2x-1 Show all of your work for each ordered pair. Ordered Pairs: (1,1) (-1, -4) (-2, -1/8) (0,1/2)

Answer 1

(1, 1) is the only one on the graph

Explanation:

To determine if an ordered pair lies on the graph, substitute the x-coordinate of the ordered pair into f(x) and evaluate. If the value equals the y-coordinate of the ordered pair then it lies on the graph

f(1) = (2 × 1) - 1 = 2 - 1 = 1 ⇒ (1, 1) lies on graph

f(- 1) = (2 × - 1) - 1 = - 2 - 1 = - 3 ≠ - 4 ⇔ (- 1, - 4 ) not on graph

f(- 2) = (2 × - 2) - 1 = - 4 - 1 = - 5 ≠ -
`(1)/(8)` ⇒ (- 2, -
`(1)/(8)`) not on graph

f(0) = (2 × 0) - 1 = 0 - 1 = - 1 ≠
`(1)/(2)` ⇒ not on graph