Question

The function f(x) is graphed on the coordinate plane. What is f(−1) ?

Answer 1

The graph displays y = -2x + 1
So, f(-1) would be:
f(-1) = -2(-1) + 1
= 2 + 1
f(-1) = 3

Answer 2

ANSWER

$f( - 1) = 3$

EXPLANATION

Method 1

We can determine that,


$f( - 1) = 3$

by tracing directly from the graph as shown in the attachment.


Method 2.


We can find the equation of the line first.

The graph passes through

(0,1) and (1,-1).


$slope = \frac{ - 1 - 1}{1 - 0} = - 2$


The equation of the line is of the form,

$y =mx + c$
where

$m = - 2$
is the slope and
$c = 1$
is the y-intercept.


This implies that,

$y = - 2x + 1$


$f( - 1) = - 2( - 1) + 1$
We evaluate to get,


$f( - 1) = 2 + 1 = 3$