Graphing with y=mx+b
Previously on MFM2P...
To determine the equation we need the y-intercept (100) and the slope (50/2 = 25).
Thus our equation is:
y = 25x + 100
Previously on MFM2P...
We can also find the equation if we are given a table:
The intercept occurs when x=0, so b=7.
Our slope is found by finding our rise and run:
m = rise = -8 - (-23) = 15 = 3
run -5 - (-10) 5
Equation: y = 3x + 7
x | y |
-10 | -23 |
-5 | -8 |
0 | 7 |
5 | 22 |
10 | 37 |
Investigate
Given an equation, can you graph it?
Try to complete this on your own. Check your answers with a partner.
When you finish a step, keep your pencil in the same position.
Investigation
Looking at all 3 investigations, can you relate the value from step 2 and 3 to the slope or y-intercept? Explain the relationship
The number from step 2 is the rise
The number from step 3 is the run
Graphing from y=mx+b
Graph:
y = x - 3
3
2
1. Plot the y-intercept.
2. Use the rise and run to plot additional points.
- Rise goes up (+) or down (-)
- Run goes right (+)
3. Draw a line through the points.
Graphing from y=mx+b
Graph:
y = x + 2
-1
4
Graphing from y=mx+b
Graph:
y = 3x - 4