How do you plot a function with 2 variables?

Question

example: y=3x+2

Answer 1

The Cartesian plane was invented just for things like that. You get a piece of graph paper, draw a line across and call it the X axis. Cross that line with a perpendicular line and call it the Y axis.

Then you can pick any value of X (let's say 2) and calculate the value of Y (6+2 = 8). You then put a point at (2, 8) where 2 is on the X axis and 8 is on the Y axis.

Your formula is a linear equation which means it will make a straight line on the Cartesian plane.

Answer 2

on a x-y plane, you plug in values for x to get a value of y.

Then, you go over x squares and go up y squares. Mark the point.

Then, you plug in another value for x and do the same thing.

Connect the points and extend the ends to create a line. Add arrows to the ends of the line and your finished.

Answer 3

This is a straight line so just find any two points on the line and then draw the line between them.

E.g if x = 0 then y = 3.

If x = 1 then y = 8.

So draw the x and y axes, then mark the points (0,3) and (1,8) and draw the straight line between them and extend it in each direction as far as you have room.

Answer 4

Set up a table of values

   x.......y

Pick any number you wish for x, solve for y. 0 is always a good number

to pick.

..x.......y....Ordered Pair

...-5.....-13.....(-5,-13)

...-2.....-4.......(-2,-4)

....0......2.......(0,2)

....4......14.....(4,14)

You get the idea.

Plot these points, then sketch the graph by drawing a curve through

the points.

The example you presented is a linear equation, and all linear equations are straight lines, so you need only 2 points. You can spot

a linear equation by finding the biggest exponent ( that ^2 thing). If it

is only ^1, as in your example then it's linear.

For other curves, finding several points is recommended, as I did'