2/18/14
Bellwork/Warm-Up
Solve this system by Substitution
2x – 3y = 15
y = 3x
Bellwork Solution
Solve this system by Substitution
2x – 3y = 14
y = 3x
Step One: Substitute 3x into first equation wherever there
is the y variable.
2x – 3(3x) = 14
Step Two: Combine terms (subtract 9x from 2x)
2x – 9x = 14
-7x = 14
Bellwork Solution, continued
Step Three: Isolate the x by dividing both sides by -7
-7 x = 14
-7
-7
x = 14 = -2
-7
Step Four: Substitute the newly found value for x into the
second equation to find y.
y = 3(-2)
y = -6
Bellwork Solution, continued
Step Five: Check your work by putting x and y values into
both equations to see if they are true.
2x – 3y = 14
Using x = -2 and y = -6
y = 3x
2x – 3y = 14
2(-2) – 3(-6) = 14
-4 – (-18) = 14
-4 + 18 = 14
14 = 14
YES, THIS IS TRUE
y = 3x
-6 = 3(-2)
-6 = -6
YES, THIS IS TRUE
So the solution is (-2, -6)
Scatterplots,
• Let’s explore . . .
• Pick a partner and write down their height.
• Measure the length of their arm using a ruler.
• Record your data. Repeat with three more classmates.
Classmate
Height
Arm Length
Scatterplots
• Do you think that there might be a
relationship between how tall
someone is and how long their arms
are?
• How could we interpret this data?
Scatterplots
Scatterplots
Scatterplots – put this in your NOTES
Scatterplots
Scatterplots - Classwork
Scatterplots
Scatterplots
Scatterplots - Classwork
Scatterplots - Classwork
Homework
p. 616, #2-6 and #9
• Due Wednesday (tomorrow)
• Attempt every problem . . . We will go over correct
answers in class.
• Corrections are due Thursday..