proportional relationships
CLICK HERE for help from Khan Academy with Proportional Relationships.
CLICK HERE for another great video about Proportional Relationships
CLICK HERE for another great video about Proportional Relationships
slope
SLOPE INTERCEPT FORM: y=mx + b
where m = to slope (rise over run)
and b= the y intercept (where does your line cross your y axis)
When going from an equation to a graph: make sure it is in slope intercept form. Then you can easily graph the y intercept (start at the origin (0,0) and go up (+) or down(-) the number of spaces that the equation states. For example if the equation is y=2x + 9, I would move up 9 spaces and put a dot. From that dot, I need to plot my slope. This number is directly in front of the x (if there is no number, just an equal sign, treat it as a 1); if it is a whole number turn it into a fraction by putting a 1 under the number. In our example (y=2x+9) our slope is 2 which means our slope would then be 2/1. We use this number by starting at the y intercept dot and rising 2 and going to the right 1 space. If the number is negative, you would go down the required number and over to the right again.
When going from a graph to an equation: First you need to find your y intercept. Start at the origin (0,0) and go up until you hit the graphed line. Then with one finger on the y intercept, and the other on the line, find another point on the line. See how many boxes you need to go up/down to hit your point on the line; this is your slope (rise/run)
you would then put it into slope intercept form.
where m = to slope (rise over run)
and b= the y intercept (where does your line cross your y axis)
When going from an equation to a graph: make sure it is in slope intercept form. Then you can easily graph the y intercept (start at the origin (0,0) and go up (+) or down(-) the number of spaces that the equation states. For example if the equation is y=2x + 9, I would move up 9 spaces and put a dot. From that dot, I need to plot my slope. This number is directly in front of the x (if there is no number, just an equal sign, treat it as a 1); if it is a whole number turn it into a fraction by putting a 1 under the number. In our example (y=2x+9) our slope is 2 which means our slope would then be 2/1. We use this number by starting at the y intercept dot and rising 2 and going to the right 1 space. If the number is negative, you would go down the required number and over to the right again.
When going from a graph to an equation: First you need to find your y intercept. Start at the origin (0,0) and go up until you hit the graphed line. Then with one finger on the y intercept, and the other on the line, find another point on the line. See how many boxes you need to go up/down to hit your point on the line; this is your slope (rise/run)
you would then put it into slope intercept form.