SOLUTION: Graph the functions: f(x) = -2x - 5. I am not doing to well with these fuctions, so any help with trying to graph one is greatly appreceated. Thanks

Algebra ->  Functions -> SOLUTION: Graph the functions: f(x) = -2x - 5. I am not doing to well with these fuctions, so any help with trying to graph one is greatly appreceated. Thanks      Log On


   

Question 67023This question is from textbook Beginning Algebra
: Graph the functions: f(x) = -2x - 5. I am not doing to well with these fuctions, so any help with trying to graph one is greatly appreceated. Thanks This question is from textbook Beginning Algebra

Found 2 solutions by Earlsdon, ankor@dixie-net.com:
Answer by Earlsdon(6294) About Me  (Show Source):
You can put this solution on YOUR website!
If you are graphing this by hand (no grahing calculator), the best way to proceed is to first replace the f(x) with y:
y+=+-2x-5 then make what is called an input/output table.
You do this by assigning a numerical value to x (start with small values to make the calculations easier) then find the corresponding value of y.
For a linear function such as this, you need only two points to draw the line.
So, let's see how this goes!
y+=+-2x-5 Substitute 0 for x and calculate the y.
y+=+-2%280%29-5
y+=+-5 So here's one point (0, -5) that you can graph on your graph paper once you have drawn the x-axis (horizontal line) and the y-axis (vertical line)
A second point can be found by letting x = 1.
y+=+-2%281%29-5
y+=+-2-5
y+=+-7 Here's the second point (1, -7)
Plot these two points on your coordinate graph and draw a straight line through them.
Here's what it should look like when you are done:
graph%28300%2C200%2C-5%2C5%2C-8%2C5%2C-2x-5%29

Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Graph the functions: f(x) = -2x - 5.
:
y = f(x)
:
y = -2x - 5
:
Choose some values for x. Substitute for x in the equation and solve for y.
Good range is from -3 to + 3. Since it is a linear equation (a straight line),
two plots will do, however a third plot will point out a mistake and more will
give you some practice.
:
Here is x = -3 as an example:
y = -2x - 5
y = -2(-3)
y = +6 - 5
y = +1
:
Do the same for x = -1 to x = +3, the table should look like this
x | y
------
-3|+1
-1|-3
0|-5
+1|-7
+2|-9
+3|-11
:
Plot these coordinates, choose a scale that will include all these values,
your graph should look like this:
+graph%28+300%2C+200%2C+-8%2C+8%2C+-12%2C+10%2C+-2x+-+5%29+
:
Study this and see how the x|y coordinates agree with this graph and it will all
make sense to you.