Finite 1.2 Graphs & Lines
The graph of a function f is the set of all points (x,y) in
the plane that satisfy the equation y = f(x)
Linear Function - written in form f(x) = mx + b where its
graph is a straight line
• also known as slope-intercept form where m is slope &
b is y-intercept
• slope determines direction & steepness of line
• y-intercept is point (0,b)
Jan 6­9:48 AM
Graph f(x) = -2/3x + 4
Dec 22­8:19 AM
Standard Form
Ax + By = C
m = -A/B
b = C/B
Dec 22­8:13 AM
Find the slope & y-intercept of the line
y = 4x - 2
y = -1/2x + 3
3x +2y = 4
2x - 5y = 10
Dec 22­8:20 AM
Horizontal line has _________ slope
Vertical line has _________ slope
Dec 22­8:34 AM
Dec 22­8:22 AM
1
Find an equation of a line with slope -2 and passes
through the point (-5, -3)
Point-Slope Form - If a line has slope m & passes
through the point (x1, y1), an equation of the line is:
y - y1 = m(x - x1)
Find an equation of a line with slope 2/3 and passes
through the point (4, -6)
Find an equation of a line passing through (7,3) & (-1,6)
Find an equation of a line passing through (-2,1) & (-4,5)
Dec 22­8:23 AM
Carlos started a paper route & decided to add $7 each
week to his savings account. By the eighth week he had
$242 in savings. Write the total savings as a function of
the number of weeks since he started his route.
Dec 22­8:25 AM
In 1990 Penn State had enrollment of 75,365 &
by 2002 it increased to 83,038. Write linear
equation to model the data. Find average annual
change in enrollment. If it continues at this
rate, what would enrollment be in 2010?
Dec 22­8:29 AM
Dec 22­8:43 AM
Finding x -intercept & y-intercept in Standard Form
Parallel lines have ___________ slope
3x - 4y = -12
Perpendicular lines have _____________ slope
x-intercept (x,0)
y-intercept (0,y)
Determine if lines are parallel, perpendicular or neither
3x + 2y = 4
6x + 4y = 12
2x - 8y = 20
Dec 22­8:33 AM
2x - 5y = 13
5x - 2y = 20
Dec 22­8:37 AM
2
Write equation of line through (1,6) parallel to 3x + y = 2
Write equation of line through (-4,5) perpendicular to
3x + 2y = 9
Dec 22­8:41 AM
Jan 3­1:56 PM
Jan 3­2:06 PM
Jan 3­2:07 PM
Jan 6­10:05 AM
3