Algebra
Lesson 5-3
Vocabulary:
Slope-intercept Form- an equation of the form y=mx+b, where m is the slope and b is the y-intercept
Example 1:
The linear equation y=mx+b is written in slope-intercept form, where the m is the slope and the b is the y-intercept.
y=mx+b.
Write an equation of the line whose slope is 3 and whose y-intercept is 6.
The linear equation y=mx+b is written in slope-intercept form, where the m is the slope and the b is the y-intercept.
y=mx+b.
Write an equation of the line whose slope is 3 and whose y-intercept is 6.
Fill in the variable m with 3 and the variable b with 6. Leave your x and y as they are.
The answer should be y=3x+6.
Wait there is a catch in the next examples.
The answer should be y=3x+6.
Wait there is a catch in the next examples.
Example 2: Write an Equation Given Two Points
On a graph you are give two points: (0,3) and (2,-1)
You need to first find the slope.
Step 1:
M=-1-3
2-0
M=-4 Or -2 So the slope is -2
2
Step 2: The line crosses the y-axis at (0,3) so, the y-intercept is 3.
Step 3: Write the equation.
y=mx+b
Fill in what you have. Since m is your slope you replace m with -2. Since b is your y-intercept you replace b with 3
Your answer should be y=-2x+3
Example 3
Solve for y.
5x-3y=6
+3y +3y
5x=3y+6
-6 -6
5x-6=3y
3 3
5/3x-2=y
M=5/3
B=-2
If you were to graph this, you would make your first point at (0, -2). You would then go up 5 and over to the right 3. You would continue until you got to the edge of the graph and place arrows on each end of the line to represent the line being continuous.
Example 4:
Solve for y.
12x=4y-6
+6 +6
12x+6=4y
4 4 4
3x+3/2=y
Solve for y.
12x=4y-6
+6 +6
12x+6=4y
4 4 4
3x+3/2=y
b=3/2
Additional Information: REMEMBER!! y=mx+b m=y sub 1 minus y sub two over
x sub 1 minus x sub two
x sub 1 minus x sub two
Online resources: http://www.purplemath.com/modules/strtlneq.htm
http://library.thinkquest.org/10030/6sif.htm
http://library.thinkquest.org/10030/6sif.htm
http://id.mind.net/~zona/mmts/functionInstitute/linearFunctions/lsif.html
http://www.explorelearning.com/index.cfm?method=cResource.dspDetail&ResourceID=88
http://www.explorelearning.com/index.cfm?method=cResource.dspDetail&ResourceID=88
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CAO, SMJ, CJH