1. Writing Equations in Slope-Intercept Form
notes 4.1
Goals:
Write equations in slope-intercept form
Use linear equations to solve real-life problems

2. Example 1 using slopes & y-intercepts to write equations
a. Write an equation of each line with a slope of 2 and a y-intercept -5 b. Write an equation of each line with a slope of -1 and a y-intercept of .

3. You Try!
Write an Equation of each line with the given slope & y-intercept. 1. slope =0 2. slope =47 y-intercept = -8 y-intercept = 0 3. slope =-9 4. slope =-32 y-intercept = -3 y-intercept = 45

4. Example 2 using graphs to write equations
Write an Equation of each line in slope-intercept form. a. b.

5. You Try!
Write an Equation of each line in slope-intercept form. a. b.

6. 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)

7. You Try!
Write an Equation of each line with the given points. 7. (-1, 2) and (0, 1) 8. (3, 0) and (0,3) 9. (0, –4) and (6, –4) 10. (–4, 3) and (-4, 6)

8. 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

9. You Try!
Write a linear function with the given values. 11. g(0) = -13 and g (6) = h(-5) = 9 and h(0) = 2

10. 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.

11. 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.

12. You Try!
Excluding hydropower, U.S. power plants used renewable energy sources to generate 105 million megawatt hours of electricity in 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 Use the model to predict the number of megawatt hours that will be generated in 2017.