Please just check that you didn’t make any typos, since that would change the answers.
Don’t forget your math tools
Mat/116 Algebra 1A
1) Determine weather the given numbers are solutions of the inequality.
5, -18, -20, -1
y – 9 > 2y – 2 Is 5 a solution? Yes or No.
5 NO
-18 YES
-20 YES
-1 NO
2) Write the set {x | x>3 } in interval notation.
Choose the correct interval
a. (3, )
3) Write interval notation for the set {x | -5 > x> -10}
Choose the correct notation
c. (-10, -5)
5) Solve. Then Graph
t + 163
The solution is {t |t -13}
-15 -14 -13 -12 -11
[------
6) Solve. -x - . The solution is {x | x __ __}.
x ≤ 7/6
7) Solve. 5x + 9 < 49
The solution is { x | x < 8}
8. Solve. 0.8x + 6 1.2x – 9
solution is { x| x __ __}
x ≥ 37.5
9. Solve. (2x -2) > 12. Use set-builder notation to describe the solution. {x | x __ __}
X > 9
10. The body mass index, I, can be used to determine an individual’s risk for heart disease. An index less than 25 indicates a low risk. The body mass index is given by the formula, or model, I = , where W = weight, in pounds, and H= height, in inches. Francis weighs 211 pounds and stands 75 inches tall. What is his approximate body mass index? Find an inequality describing all weights W that Francis can have and be in the low risk category.
(assuming the standard mathlab rounding, and the standard mathlab formulas)
BMI = 26
Low risk = 200
11) Bayside Insurance offers two health plans. Under plan A, Giselle would have to pay the first $90 of the medical bills, plus 40% of the rest. Under plan B, Giselle would pay the first $130, but only 35% of the rest. For what amount of medical bills will plan B save Giselle money? Assume she has over $130 in bills.
Giselle would save with plan B if she had more than $ ____ in bills.
610
12) Find the intersection
{ 2, 4, 6, 9} {3, 5, 7}
EMPTY SET
13) Write the solution in interval notation. X < 9 and x -6
The question is missing a symbol.
14) Solve. -8 3x + 4 and 3x + 4 < 19
The solution is {x |__ x < __ }
-4 ≤ x ≤ 5
15) Solve. -4 < x + 4 < 11 The solution is {x| __ < x < __}
-8 < x < 7
16) -22 4x – 5 - 4 The solution is {x| __ x __}
-17/4 ≤ x ≤ 1/4
17) Write solution using interval notation. X < -3 or x > 0
(-inf, -3) U (0, inf)
18) solve. x + 6 < -7 or x + 6 > 2. The solution is {x | x < __ or x > __}
x < -13 or x > -4
19) - 7 or 1 The solution is {x | x __ or x __}
4x-5 ≤ -70 or 4x-5≥10
4x ≤ -65 or 4x ≥ 15
x ≤ -65/4 or x ≥ 15/4
20) In order to achieve maximum results from aerobic exercise, one should maintain one’s heart rate at a certain level. A 45 –yr-old woman with a resting heart rate of 75 heart beats per minute should keep her heart rate between 135 and 155 beats per minute while exercising. She checks her pulse for 10 sec while exercising. What should the number of beats be?
The number of beats in 10 sec should be between __ and ___ beats.
23 to 26
22) Graph the inequality on a plane. y > 6x. ( If you can give me the points I can graph it)
Dotted line
Shade above
Goes through (0,0), (1, 6), (-1, -6)
23) Graph the inequality on a plane. 3x + 4y 12 ( Same as above)
Solid line, shade below, goes through (4, 0) and (0, 3)
24) Graph the inequality on a plane. 5x – 4 9x + y (Same as above)
Shade right, solid line
Goes through (0, -4), (-4, 12), (4, 20)
27) Graph the system of inequalities. y -3 x 5
28) Graph the system of inequalities. x + 3y 9
3x + y 9
x 0
y 0
Appendix F
Buying a Home
For most people, buying a house is a great investment that can offer security in an uncertain world, but buying a house is also a commitment.
Application Practice
Answer the following questions. Use Equation Editor to write mathematical expressions and equations. First, save this file to your hard drive by selecting Save As from the File menu. Click the white space below each question to maintain proper formatting.
- Suppose you are in the market for a new home and are interested in a new housing community under construction in a different city.
a)The sales representative informs you that there are two floor plans still available, and that there are a total of 56 houses available. Use x to represent floor plan #1 and y to represent floor plan #2. Write an equation that illustrates the situation.
x + y = 56
b)The sales representative later indicates that there are 3 times as many homes available with the second floor plan than the first. Write an equation that illustrates this situation. Use the same variables you used in part a.
3x = y
c)Use the equations from part a and b of this exercise as a system of equations. Use substitution to determine how many of each type of floor plan is available. Describe the steps you used to solve the problem.
Substitute the second equation into the first:
x + 3x = 56
Add:
4x = 56
Divide by 4:
x = 14
y = 3x = 3*14 = 42
14 of plan 1
42 of plan 2
d)What are the intercepts of the equation from part a of this problem? What are the intercepts from part b of this problem? Where would the lines intersect if you solved the system by graphing?
Part a intercepts:
x = 56 and y = 56
(0, 56) and (56, 0)
Part b intercepts:
Both intercepts are at (0,0)
The lines would intersect at x = 14, y = 42, which is the point (14,42).
- As you are leaving the community, you notice another new community just down the street. Because you are in the area, you decide to inquire about it.
a)The sales representative here tells you they also have two floor plans available, but they only have 38 homes available. Write an equation that illustrates the situation. Use x and y to denote floor plan #1 and floor plan #2 respectively.
x + y = 38
b)The representative tells you that floor plan #1 sells for $175,000 and floor plan #2 sells for $200,000. She also mentions that all the available houses combined are worth $7,200,000. Write an equation that illustrates this situation. Use the same variables you used in part a.
175000x + 200000y = 7200000
c)Use elimination to determine how many houses with each floor plan are available. Explain how you arrived at your answer.
Multiply the first equation by -175000:
-175000x – 175000y = -6650000
Add to the second equation:
25000y = 550000
Divide by 25000:
y = 22
x + 22 = 38
x = 38 – 22 = 16
16 of plan 1
22 of plan 2
- You recently started the paperwork to purchase your new home, and you were just notified that you can move into the house in 2 weeks. You decide to hire a moving company, but are unsure which company to choose. You search online and are interested in contacting two companies, Heavy Lifters and Quick Move, to discuss their rates. Heavy Lifting charges an $80 fee plus $35 per hour. Quick Move charges $55 per hour with no additional fees.
a)Which mover provides a better deal for 2 hours of work? How did you arrive at your answer?
Heavy:
80 + 35*2 = 80 + 70 = 150
Quick:
55*2 = 110
Quick Move has the better deal.
b)Which mover provides a better deal for 15 hours of work? How did you arrive at your answer?
Heavy:
80 + 35*15 = 80 + 525 = 605
Quick:
55*15 = 825
Heavy Lifters has the better deal.
c)For what values h (hours) does Quick Move offer the better deal? Express your answer as an inequality. Explain how you reached your answer.
Quick Move must be less than Heavy Lifters:
55h < 80 + 35h
Subtract 35h:
20h < 80
Divide by 20:
h < 4
For less than 4 hours, Quick Move has the better deal.