5.1-5.2 Writing & Using slope-intercept form
What is slope intercept form? _________________________
What does m mean? _____________
What does b mean? _____________
How do you find slope?
Sometimes you are not given the slope and y-intercept and need to find them!
Ex 1. Find the equation of a line in Slope-intercept form that has a slope of -4 and
passes through the point (-1, 3).
a) Plug in the x-value (x), y-value (y), and slope (m) into 𝑦 = 𝑚𝑥 + 𝑏 and solve for b
b) Re-write the equation in slope-intercept form: ____________________
Ex 2. Find the equation of a line in Slope-intercept form of a line that passes
through (3, -1) and (6, 4).
a) Calculate the slope (m):
b) Choose one of the 2 given points, plug in the x–value (x), y-value (y), & slope (m)
to 𝑦 = 𝑚𝑥 + 𝑏 and solve for b:
c) Re-write the equation in slope-intercept form: ___________________
You Try:
Based on the given information find the equation of the line in slope-intercept form
1. Slope= 2 Point: (5, 1)
1
2. Slope= -2
Point: (5, -5)
3. 𝑚 = 2 Point: (-3, -11)
4. 𝑚 = 2 Point: (6, 3)
5. (-2, 5) (2, -1)
6. (3, 2) (4, 9)
7. (-2, 8) (-6, 0)
8. (-5, 4) (-2, − 4)
3
3
Real World Problems & Applications
Ex. 1:
A recording studio charges musicians an initial fee of $50 to record an album.
Studio time costs an additional $35 per hour.
a) Write an equation that gives the total cost of an album as a function of studio
time.
b) Find the total cost of recording an album that takes 10 hours of studio time.
Ex. 2:
Your gym membership costs $33 per month after an initial membership fee. You
paid a total of $228 after 6 months.
a) Write an equation that gives the total cost as a function of the length of your
gym membership.
b) Find the total cost after 9 months
Ex. 3:
In BMX racing, racers purchase a one year membership to a track. They also pay an
entry fee for each race at that track. One racer paid a total of $125 after 5
races. A second racer paid a total of $170 after 8 races.
a) How much does the track membership cost?
b) What is the entry fee per race?