Homework Help: Need help

1. Jan 14, 2006

Mt. Nixion

I am doing this worksheet where I have to graph the following,

1.

A. x=-3
B. y=-1
C. x-y=2
D.x+y=6

2.

A. y=x
B.y=-x
C.y=2x-6
D.y=-1/2x-6

I know you don't do the homework for other people, but could you show me how to do these please?

2. Jan 14, 2006

HallsofIvy

Here's the important hint: every one of those functions is linear. Each graph is a straight line. Two points determine a straight line. Determine the y value for two different values of x, plot the points, draw the line throught those two points.

For example, in 1c) when x= 1, the equation x-y= 2 becomes 1- y= 2. What is y? when x= 0, the equation becomes 0-y= 2. What is y?

Don't forget that an equation means exactly what it says. For 1b) the equation is y= -1 which doesn't have an x in it! When x= 0, what is y? When x= 1, what is y?

The one "hard" one is the very first: 1a) x= -3. Since you are told that x must be -3, it makes no sense to ask "if x= 0, what is y?" But you can do it the other way around: When y= 0, what is x? Plot that point. When y= 1, what is x? Plot that point. Draw the line through those points.

3. Jan 15, 2006

Mt. Nixion

I do not quite understood what you said, HallsofIvy. Could you give some more detail or can anyone else help me?

4. Jan 15, 2006

arildno

For ALL these exercises, you are to plot ALL points in the x,y-plane satisfying the given equation (ideally, that is).

Taking the first:
If you plot ALL points in the x,y-plane whose x-coordinates are all equal to -3 (that's what the equation requries), and no other points, what sort of curve do you end up with?

5. Jan 16, 2006

HallsofIvy

What DO you know how to do? Can you graph a single point?

Take a look at x- y= 2. When x= 0 what is y? Can you plot that point: (0, __)? When y= 0 what is x? Can you graph that point: (__, 0)?

If you can do that, draw the line through those two points.