graphing math problems

Question

the line passing through (3, -1) with slope -2/3

Answer 1

Nick,

 

Use equation y = mx+c where m is the slope of the equation and c is the y intercept.

 

Using the point (3, -1) and substituting in the above equation for x and y

-1 = (-2/3)(3) + c

-1 = -2 + c

c = 1

so the y intercept is (0,1)

 

Now draw a line passing through (3,-1) and (0,1).

 

You have your answer.

Answer 2

I am assuming that you're trying to graph this line. You always start by plotting the point that the line passes through. The slope is a set of instructions that will take you from one nice intersection point to the next. The numerator tell you how far up or down you will have to count since it represents the change in y, or the vertical change. The denominator is the change in x, or how far left or right you have to count.

 

So from the point you plotted, (3,-1), you need to count 2 boxes down and then 3 boxes to the right. You need to repeat this until you've reached the edge of your graph. You then may have to extent the line in the opposite direction which means that you have to reverse this pattern, that is to count 2 up, then 3 to the left, repeating until you've crossed to the edge of your graph.

 

It is important to realize that when you are counting boxes, you are counting the length of the side of the square. so if you followed these instruction from (3,-1), your next point should have come out to be (1,2).

 

Hope this helps.