Question

Evaluate the function at x = –2. A. y = –4 B. y = 0 C. y = 2 D. y = 3

Answer 1

From the graph, identify the x=-2 point on x axis,
(is it 2 units to left of origin.)

now, imagine a vertical line through it.
This vertical line intersects the given line at which point?
The y co-ordinate of this point is your answer.

From the given graph,
the vertical line intersects at (-2,3)
so y= 3 it is :)

Answer 2

The function is represented by the straight line, slightly sloping upwards (as x goes to the right).  This is called a positive slope.

To evaluate the function at x=-2, we usually write f(x)=? When x=-2, we write f(-2)=?

To evaluate, check the vertical lines, find the one that crosses x=-2 on the x-axis.  This is the second line (-2) to the left of the y-axis.

Now examine this line and find where it crosses the slanted line.  Since it crosses exactly half-way between 2 and 4 on the y-axis, we say that y=3 is the value of f(-2), or mathematically, we say
f(-2)=3.