How to Draw Linear EquationsDate: 06/07/99 at 23:05:46 From: V Subject: How to draw linear equations I have a lot of trouble drawing linear equations. Under the y = mx+b formula, say I had y = (2/3)x + 5. How would I draw that? How would I go about finding other points? Date: 06/07/99 at 23:27:13 From: Doctor Jeremiah Subject: Re: How to draw linear equations Hi there. Getting a mental picture of what an equation looks like is not always easy. But there are clues to help us. y = mx + b is used for straight lines, so anything that fits that equation is a straight line. y = (2/3)x + 5 The value of b is the y-intercept, and because b = 5 the line crosses the y-axis at y = 5. So we will put a mark on our graph at 5 on the y-axis. | | | | (0,5) ==> X | | | | ------------+----------------- | | | | Then we notice that the slope is 2/3. Slope is measured in rise divided by run. Since the slope is 2 divided by 3 then each step is a rise of 2 and a length of 3. So the second point will be 2 above the first point and 3 over to the right. | | (3,5+2) ==> X | | | two up | | (0,5) ==> X --three over-- | | | | ------------+----------------- | | | | Now that we have two points we can take a ruler and draw a straight line that touches both points and the graph is done. If the slope is negative then the rise will be less than zero. This means that the second point will be below the first point (but still to the right). Let me know if you need more details. - Doctor Jeremiah, The Math Forum http://mathforum.org/dr.math/ |
Search the Dr. Math Library: |
[Privacy Policy] [Terms of Use]
Ask Dr. Math^{TM}
© 1994- The Math Forum at NCTM. All rights reserved.
http://mathforum.org/dr.math/