graph the functions f(x)= -2x - 5?

Question

can anyone help me out?

Answer 1

Hi!

So, what you are looking at is a linear equation. You can tell this because there is only one instance of the variable x, and it is not raised to any power. So, the graph will take the form of a line.

All linear equations take the form f(x) = mx + b

Where m is typically called the "slope" and b is called the "y-intercept". The y-intercept is the point on the graph where the function intercepts the y-axis (the one that goes from top to bottom on the graph). So, right away you can tell that the y-intercept in your equation is -5 (negative 5). What this means is that the graph intercepts the y-axis at the -5, or in other words, there is a point on the graph at the location (0,-5). You can put a dot there.

The next thing you need to see is the slope. In you equation, the slope is -2 (negative 2). Slope really means "rise over the run", or in other words, how much the graph rises for every point it goes to the right. A slope of negative 2 means that for every increase in x of one unit, the y value decreases by negative 2.

So, starting at the point (0,-5) which we determined above, go down 2 units and to the right one unit (putting you at the point (1,-7). That's another point. You can do it again and find the next point which is (2,-9) and put another point. You now can put your ruler on the graph and draw the rest of it.

It's good to understand how this type of equation works. You could have also made a table of x values and y values, and simply computed a series of y values for a series of x values (that you picked). Then you could have drawn the graph also. But understanding this type of equation will help you in the future.

Answer 2

Just make a T-chart. It's a linear function with slope of -2 (for every x it gains, it loses 2 y's), and it's offset 5, so the point (0, -5) is on the graph.

Answer 3

inter the equation on this website and it will show you how the graph would look like.
you don't need to write the f(x) = -2x - 5 but just enter it exactly like this: -2x-5

http://72.14.253.104/search?q=cache:VCn4L5eXmw4J:www.coolmath.com/graphit/index.html+online+graph&hl=en&gl=ca&ct=clnk&cd=3

good luck