Post on 17-Dec-2015
Over Lesson 8–2
A. A
B. B
C. C
D. D
Which equation best describes the sequence 9, 10, 11, 12, …?
Find the 22nd term of the sequence 7, 10, 13, 16, ….
Jimmy increased his trumpet practice by 10 minutes each week. He practiced 15 minutes during Week 1. How many minutes did he practice during Week 12?
You used functions to describe relationships between two quantities. (Lesson 1–5)
• Solve linear equations with two variables.
• Graph linear equations using ordered pairs.
• linear equation
• x-intercept
• y-intercept
An equation in which the variables appear in separate terms and neither variable contains an exponent other than 1. The graph of a linear equation is a straight line.
The x-coordinate of a point where a graph crosses the x-axis (x, 0)
The y-coordinate of a point where a graph crosses the y-axis (0, y)
Use a Table of Ordered Pairs
Find four solutions of y = 4x + 3. Write the solutions as ordered pairs.
Choose four values for x. Then substitute each value into the equation to solve for y. There are many possible solutions. The solutions you find depend on which x-values you choose.
Use a Table of Ordered Pairs
Sample Answer: Four possible solutions are (0, 3), (1, 7), (2, 11), and (3, 15).
A. A
B. B
C. C
D. D
A. (1, –2), (3, 2), (5, 1), and (7, 10)
B. (–2, 0), (0, –4), (2, 0), and (4, 4)
C. (0, –4), (1, –2), (2, 2), and (3, –1)
D. (0, –4), (1, –2), (2, 0), and (3, 2)
Find four solutions of y = 2x – 4.
Use Function Equations
BUSINESS At a local software company, Level 1 employees x earn $48,000 and Level 2 employees y earn $24,000. Find four solutions of 48,000x + 24,000y = 216,000 to determine how many employees at each level the company can hire for $216,000. Explain each solution.
First, rewrite the equation by solving for y.
Use Function Equations
48,000x + 24,000y = 216,000 Write the equation.
24,000y = 216,000 – 48,000x Subtract 48,000x from each side.
Divide each side by 24,000.
y = 9 – 2x Simplify.
Use Function Equations
Choose four x-values and substitute them into y = 9 – 2x.
Sample Answer: (0, 9), (1, 7), (2, 5), and (3, 3)0 employees at Level 1, 9 employees at Level 21 employee at Level 1, 7 employees at Level 22 employees at Level 1, 5 employees at Level 23 employees at Level 1, 3 employees at Level 2
A. A
B. B
C. C
D. D
A. 0 hardbacks, 42 paperbacks3 hardbacks, 24 paperbacks5 hardbacks, 12 paperbacks7 hardbacks, 0 paperbacks
B. 0 hardbacks, 14 paperbacks1 hardbacks, 12 paperbacks2 hardbacks, 10 paperbacks3 hardbacks, 8 paperbacks
C. 0 hardbacks, 42 paperbacks3 hardbacks, 24 paperbacks5 hardbacks, 9 paperbacks7 hardbacks, 7 paperbacks
D. 0 hardbacks, 14 paperbacks1 hardbacks, 8 paperbacks2 hardbacks, 2 paperbacks3 hardbacks, –4 paperbacks
BOOKS At a local bookstore, hardbacks are on sale for $6 and paperbacks are on sale for $3. Bob has $42 to spend on books. Find four solutions to determine how many books of each type Bob can buy with his $42.
Graph a Linear Function
Graph y = x + 2.
Step 1 Find the x-intercept.
To find the x-intercept, let y = 0.
y = x + 2 Write the equation.
0 = x + 2 Replace y with 0.
–2 = x Subtract 2 from each side.
Since x = –2 when y = 0, graph the ordered pair (–2, 0).
Graph a Linear Function
Step 2 Find the y-intercept.
y = x + 2 Write the equation.
y = 0 + 2 Replace x with 0.
y = 2 Simplify.
Since y = 2 when x = 0, graph the ordered pair (0, 2).
Step 3 Connect the pointswith a line.
Graph a Linear Function
Check Check another point in the equation. Ifx = 1, y = 1 + 2 or 3. Notice that (1, 3) is onthe graph of the line.