Download Y-intercept

DO YOU REMEMBER?
• Ordered Pairs?
• Two-Dimensional Graphs?
• Functions?
• Plotting Points?
• Domain and Range?
• Single-Variable Equations?
WHAT IS SLOPE-INTERCEPT FORM?
 Slope-Intercept form is a Function
 Slope-Intercept form has two variables
 Slope-Intercept form is for a straight line
 Slope-Intercept form is in Two Dimensions
 Slope-Intercept form has four parts
SLOPE-INTERCEPT EQUATION
The number
you plug in
(variable)
The number you
get out (variable)
Y = mX + b
The slope of
the function
(constant)
The Y-intercept
of the function
(constant)
SLOPE AND Y-INTERCEPT
Slope is the difference between two ordered pairs
(y2-y1)
m=
(x2-x1)
Y1 and x1 are the first ordered pair (x1,y1)
Y2 and x2 are the second ordered pair (x2,y2)
Y-intercept is the place where the line crosses the Y-axis
Y = mX + b
When X = 0, then Y = b (0,b)
SLOPE-INTERCEPT EQUATION
(0,3)
3
X, 0 and 3
2
(3,1)
Y, 3 and 1
(1-3)
m=
(3-0)
m = -2/3
b=3
Slope-Intercept Form
Y = -(2/3)X + 3
USING SLOPE-INTERCEPT FUNCTIONS
You select a whole number
You plug it into the equation for X
You solve the equation with the number you plugged in
You write the number you get down with the other number as an
ordered pair
• You plot the ordered pair onto a graph
•
•
•
•
SLOPE-INTERCEPT EQUATION
Slope-Intercept Form
Y = -(2/3)X + 3
3
(-3,5)
2
(0,3)
(3,1)
(2, 1.67)
3
2
(6,-1)
X
Y
0
3
3
1
-3
5
6
-1
2
-1.67
IN CONCLUSION…
• Slope-Intercept Form is for a straight line
• The equation is Y = mX + b
• m is the slope; b is the y-intercept
• You plug in a point for X and get a Y
• The numbers for X and Y are an ordered pair