Function Behavior Analysis: Multiplying Numbers by -1

Question

Determine whether the function is increasing, decreasing, or constant. For each function check your answers with a graph or table.

For each number, multiply by $(-1)$ .

00:00 Is the function increasing, decreasing, or constant?

00:03 Let's draw the function graph

00:12 Let's substitute X values and find the corresponding Y values

00:45 We can see that the function is decreasing

00:49 And this is the solution to the question

The function is:

$f(x)=(-1)x$

Let's start by assuming that x equals 0:

$f(0)=(-1)\times0=0$

Now let's assume that x equals minus 1:

$f(-1)=(-1)\times(-1)=1$

Now let's assume that x equals 1:

$f(1)=(-1)\times1=-1$

Now let's assume that x equals 2:

$f(2)=(-1)\times2=-2$

Let's plot all the points on the function graph:

We can see that the function we got is a decreasing function.

Decreasing