# Functions and graphs

• Sep 2nd 2008, 02:34 PM
cokeclassic
Functions and graphs
Question: If f(x) = -1, what is x? what point(s) are on the graph of f?

f(x) = 2x^2 -x -1

Is x 0? How am I suppose to get the points? :/
• Sep 2nd 2008, 03:00 PM
skeeter
Quote:

Originally Posted by cokeclassic
Question: If f(x) = -1, what is x? what point(s) are on the graph of f?

f(x) = 2x^2 -x -1

Is x 0? How am I suppose to get the points? :/

$2x^2 - x - 1 = -1$

$2x^2 - x = 0$

$x(2x - 1) = 0$

$x = 0$ and $x = \frac{1}{2}$

so, the points on the graph where f(x) = -1 are (0, -1) and (1/2, -1)
• Sep 2nd 2008, 03:36 PM
cokeclassic
thanks