Writing Linear Equations
Given the Slope and a Point
Yeo Chang Yoon
Kris
5.2
Writing Linear Equations Given t
he Slope and a Point
By: Yeo Chang, and Kris
Example 3
• The number of trips increased by about 26
million per year, so you know the slope is
m=26. You also know that (t,y) = (8,740) is
a point on the line, because 740 million tri
ps were taken in 1993, 8 years after 1985
Solution (a.
•
•
•
•
y=mt + b
740=(26)(8)+b
740=208+b
532=b
Write slope-intercept form
Substitute 26 for m, 8 for t, and 740 for y
Simplify
The y-intercept is b=532
Thank you fro
watching
Writing an Equation of a Line
Write an equation of the line that passes through the
point (2,6) and has a slope of 5.
y = mx + b
6 = 5(2) + b
6 = 10 + b
-4 = b
y = 5x – 4
Writing Equations of Parallel Lines
Find the equation of the line that is parallel to the line
y = -5x + 3 and passes through the point (2,2)
y = -5x + b
2 = -5(2) + b
2 = -10 + b
12 = b
y = -5x + 12
Write an equation of the line that has the
given x-intercept and slope.
x-intercept = 4
Slope = 3
y
= mx + b
0
= 3(4) + b
0 = 12+ b
- 12 = b
y = 3x - 12
Your turn
Write an equation of the line that passes
through (5,3) and has a slope of -5.
y = mx + b
3 = -5(5) + b
3 = -25 + b
28 = b
y = -5x + 28