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Writing Equations in Slope-Intercept Form
notes 4.1
Goals:
• Write equations in slope-intercept form
• Use linear equations to solve real-life
problems
Example 1
using slopes & y-intercepts to write equations
a. Write an equation of each line with a slope of 2 and a yintercept -5
b. Write an equation of each line with a slope of -1 and a yintercept of .
You Try!
Write an Equation of each line with the given slope & yintercept.
1. slope =0
y-intercept = -8
3. slope =-9
y-intercept = -3
2. slope =47
y-intercept = 0
4. slope =-32
y-intercept = 45
Example 2
using graphs to write equations
Write an Equation of each line in slope-intercept form.
a.
b.
You Try!
Write an Equation of each line in slope-intercept form.
a.
b.
Example 3
using points to write equations
a) Write an equation of the line that passes through
the given points (3,5) and (0,-2).
b) Write an equation of the line that passes through
the given points (0,2) and (–7,11)
You Try!
Write an Equation of each line with the given points.
7. (-1, 2) and (0, 1)
9. (0, –4) and (6, –4)
8. (3, 0) and (0,3)
10. (–4, 3) and (-4, 6)
Example 4
writing a linear equation
a. Write a Linear function f with the values f(-3)=4 and
f(0)=12
b. Write a Linear function f with the values f(0)=25 and
f(7)=36
You Try!
Write a linear function with the given values.
11. g(0) = -13 and g (6) = -4
12. h(-5) = 9 and h(0) = 2
Core Vocabulary
Linear Model – a linear function that models a real-life
situation. When a quantity y changes at a constant
rate with respect to a quantity x, you can model the
relationship of y and x with a linear function.
Example 5
modeling with mathematics
A recording studio charges musicians an initial fee of
$50 to record an album. Studio time costs an
additional $75 per hour. Write a linear model that
represents the total cost of recording an album as a
function of studio time (in hours). Is it less expensive to
purchase 12 hours of recording time at the studio or a
$750 music software program that you can use to
record on your own computer? Explain.
You Try!
Excluding hydropower, U.S. power plants used
renewable energy sources to generate 105 million
megawatt hours of electricity in 2007. By 2012, the
amount of electricity generated had increased to 219
million megawatt hours. Write a linear model that
represents the number of megawatt hours generated
by non-hydropower renewable energy sources as a
function of the number of years since 2007. Use the
model to predict the number of megawatt hours that
will be generated in 2017.