Date post: | 18-Dec-2015 |
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How do you find b?
How do you find b?
“DRY”
How do you find b?
How do you find b (dry)?
Review
What is slope-intercept form?Y = mX + b
?
Review
What is slope-intercept form?Y = mX + b
Input
Review
What is slope-intercept form?Y = mX + b
?
Review
What is slope-intercept form?Y = mX + b
Output
Review
What is slope-intercept form?Y = mX + b
?
Review
What is slope-intercept form?Y = mX + b
Rate of changea.k.a. Slope
Review
What is slope-intercept form?Y = mX + b
?
Review
What is slope-intercept form?Y = mX + b
Starting amounta.k.a. ‘y-intercept’
How do you find b?
Riddle
I started with some money.
Every week I earned $100.
After 4 weeks, I had $900.
How much did I start with?
b
m X Y
Riddle
I started with some money.
Every week I earned $100.
After 4 weeks, I had $900.
How much did I start with?
b
m X Y
4 900
Riddle
I started with some money.
Every week I earned $100.
After 4 weeks, I had $900.
How much did I start with?
b
m X Y01234 900
Riddle
I started with some money.
Every week I earned $100.
After 4 weeks, I had $900.
How much did I start with?
b
m X Y0123 8004 900
Riddle
I started with some money.
Every week I earned $100.
After 4 weeks, I had $900.
How much did I start with?
b
m X Y012 7003 8004 900
Riddle
I started with some money.
Every week I earned $100.
After 4 weeks, I had $900.
How much did I start with?
b
m X Y01 6002 7003 8004 900
Riddle
I started with some money.
Every week I earned $100.
After 4 weeks, I had $900.
How much did I start with?
b
m X Y0 5001 6002 7003 8004 900
$500
4 * 100Gained $400
900 – 400Started with $500
Write the equation of the linear relationship with:
m: 100
point: (4, 900).
mY = mX + b
900 = 100(4) + b
900 = 400 + b–400– 400
500 = b
x y
“DRY”
Y = 100X + 500
Ex. 1: Write the equation of a line that goes through (7, 8) and has a slope of 2.
Y = mX + b
NEED m and b
How to use (7, 8)???
Input Output
NEED b!!!
X Y
Y = 2X – 6
Ex. 1: Write the equation of a line that goes through (7, 8) and has a slope of 2.
Y = mX + b
How to use (7, 8)???
Input Output
8 = 2(7) + b8 = 14 + b
-6 = b
Y = 2X – 6
– 14– 14
X Y
Ex. 2: Write the equation of a line with this information:
slope: -5
point: (-4, 3)
Y = mX + b3 is NOT
y-intercept!!!
X Y
m
Ex. 2: Write the equation of a line with this information:
slope: -5
point: (-4, 3)
Y = mX + b
3 = -5(-4) + b3 = 20 + b
-17 = b
Y = -5X – 17
– 20– 20
X Y
m
Ex. 3: Write the equation of a line that goes through (0, 8) and has a slope of 2.
Y = mX + b
NEED m and b Y = 2X + 8
Ex. 3: Write the equation of a line that goes through (0, 8) and has a slope of 2.
Y = mX + b
NEED m and b Y = 2X + 8
Ex. 4: Write a rule from this information:
m: -4 point: (8, -2)
Y = mX + b
-2 = -4(8) + b-2 = -32 + b
30 = bY = -4X + 30+ 32+ 32
X Ym
Ex. 5: Write an equation for a relationship with this information:
m: zero.
point: (-4, -6)
Y = -6
The change in y when x increases by one
Ex. 6: Write an equation for a relationship with this information:
m: undefined.
point: (-4, -6)
X = -4
The change in y when x increases by one
The End