9.E: Review Exercises and Sample Exam
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Review Exercises
Solve by extracting the roots.
- x2−16=0
- y2=94
- x2−27=0
- x2+27=0
- 3y2−25=0
- 9x2−2=0
- (x−5)2−9=0
- (2x−1)2−1=0
- 16(x−6)2−3=0
- 2(x+3)2−5=0
- (x+3)(x−2)=x+12
- (x+2)(5x−1)=9x−1
- Answer
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1. ±16
3. ±3√3
5. ±5√33
7. 2,8
9. 6±√34
11. ±3√2
Find a quadratic equation in standard form with the given solutions.
- ±√2
- ±2√5
- Answer
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1. x2−2=0
Complete the square.
- x2−6x+?=(x−?)2
- x2−x+?=(x−?)2
- Answer
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1. x2−6x+9=(x−3)2
Solve by completing the square.
- x2−12x+1=0
- x2+8x+3=0
- y2−4y−14=0
- y2−2y−74=0
- x2+5x−1=0
- x2−7x−2=0
- 2x2+x−3=0
- 5x2+9x−2=0
- 2x2−16x+5=0
- 3x2−6x+1=0
- 2y2+10y+1=0
- 5y2+y−3=0
- x(x+9)=5x+8
- (2x+5)(x+2)=8x+7
- Answer
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1. 6±√35
3. 2±3√2
5. −5±√292
7. −32,1
9. 8±3√62
11. −5±√232
13. −2±2√3
Identify the coefficients a, b, and c used in the quadratic formula. Do not solve.
- x2−x+4=0
- −x2+5x−14=0
- x2−5=0
- 6x2+x=0
- Answer
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1. a=1,b=−1, and c=4
3. a=1,b=0, and c=−5
Use the quadratic formula to solve the following.
- x2−6x+6=0
- x2+10x+23=0
- 3y2−y−1=0
- 2y2−3y+5=0
- 5x2−36=0
- 7x2+2x=0
- −x2+5x+1=0
- −4x2−2x+1=0
- t2−12t−288=0
- t2−44t+484=0
- (x−3)2−2x=47
- 9x(x+1)−5=3x
- Answer
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1. 3±√3
3. 1±√136
5. ±6√55
7. 5±√292
9. −12,24
11. 4±3√6
Use the discriminant to determine the number and type of solutions.
- −x2+5x+1=0
- −x2+x−1=0
- 4x2−4x+1=0
- 9x2−4=0
- Answer
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1. Two real solutions
3. One real solution
Solve using any method.
- x2+4x−60=0
- 9x2+7x=0
- 25t2−1=0
- t2+16=0
- x2−x−3=0
- 9x2+12x+1=0
- 4(x−1)2−27=0
- (3x+5)2−4=0
- (x−2)(x+3)=6
- x(x−5)=12
- (x+1)(x−8)+28=3x
- (9x−2)(x+4)=28x−9
- Answer
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1. −10,6
3. ±15
5. 1±√132
7. 1±3√32
9. −4,3
11. 5±√5
Set up an algebraic equation and use it to solve the following.
- The length of a rectangle is 2 inches less than twice the width. If the area measures 25 square inches, then find the dimensions of the rectangle. Round off to the nearest hundredth.
- An 18-foot ladder leaning against a building reaches a height of 17 feet. How far is the base of the ladder from the wall? Round to the nearest tenth of a foot.
- The value in dollars of a new car is modeled by the function V(t)=125t2−3,000t+22,000, where t represents the number of years since it was purchased. Determine the age of the car when its value is $22,000.
- The height in feet reached by a baseball tossed upward at a speed of 48 feet/second from the ground is given by the function h(t)=−16t2+48t, where t represents time in seconds. At what time will the baseball reach a height of 16 feet?
- Answer
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1. Length: 6.14 inches; width: 4.07 inches
3. It is worth $22,000 new and when it is 24 years old.
Determine the x- and y-intercepts.
- y=2x2+5x−3
- y=x2−12
- y=5x2−x+2
- y=−x2+10x−25
- Answer
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1. x-intercepts: (−3,0),(12,0); y-intercept: (0,−3)
3. x-intercepts: none; y-intercept: (0,2)
Find the vertex and the line of symmetry.
- y=x2−6x+1
- y=−x2+8x−1
- y=x2+3x−1
- y=9x2−1
- Answer
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1. Vertex: (3,−8); line of symmetry: x=3
3. Vertex: (−32,−134); line of symmetry: x=−32
Graph. Find the vertex and the y-intercept. In addition, find the x-intercepts if they exist.
- y=x2+8x+12
- y=−x2−6x+7
- y=−2x2−4
- y=x2+4x
- y=4x2−4x+1
- y=−2x2
- y=−2x2+8x−7
- y=3x2−1
- Answer
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1.
Figure 9.E.1 3.
Figure 9.E.2 5.
Figure 9.E.3 7.
Figure 9.E.4
Determine the maximum or minimum y-value.
- y=x2−10x+1
- y=−x2+12x−1
- y=−5x2+6x
- y=2x2−x−1
- The value in dollars of a new car is modeled by the function V(t)=125t2−3,000t+22,000, where t represents the number of years since it was purchased. Determine the age of the car when its value is at a minimum.
- The height in feet reached by a baseball tossed upward at a speed of 48 feet/second from the ground is given by the function h(t)=−16t2+48t, where t represents time in seconds. What is the maximum height of the baseball?
- Answer
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1. Minimum: y=−24
3. Maximum: y=95
5. The car will have a minimum value 12 years after it is purchased.
Rewrite in terms of i.
- √−36
- √−40
- √−825
- -√−19
- Answer
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1. 6i
3. 2√2i5
Perform the operations.
- (2−5i)+(3+4i)
- (6−7i)−(12−3i)
- (2−3i)(5+i)
- 4−i2−3i
- Answer
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1. 5−i
3. 13−13i
Solve.
- 9x2+25=0
- 3x2+1=0
- y2−y+5=0
- y2+2y+4
- 4x(x+2)+5=8x
- 2(x+2)(x+3)=3(x2+13)
- Answer
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1. ±33
3. 12±i√192
5. ±i√52
Sample Exam
Solve by extracting the roots.
- 4x2−9=0
- (4x+1)2−5=0
- Answer
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1. ±32
Solve by completing the square.
- x2+10x+19=0
- x2−x−1=0
- Answer
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1. −5±√6
Solve using the quadratic formula.
- −2x2+x+3=0
- x2+6x−31=0
- Answer
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1. −1,32
Solve using any method.
- (5x+1)(x+1)=1
- (x+5)(x−5)=65
- x(x+3)=−2
- 2(x−2)2−6=3x2
- Answer
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1. −65,0
3. −2,−1
Set up an algebraic equation and solve.
- The length of a rectangle is twice its width. If the diagonal measures 6√5 centimeters, then find the dimensions of the rectangle.
- The height in feet reached by a model rocket launched from a platform is given by the function h(t)=−16t2+256t+3, where t represents time in seconds after launch. At what time will the rocket reach 451 feet?
- Answer
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1. Length: 12 centimeters; width: 6 centimeters
Graph. Find the vertex and the y-intercept. In addition, find the x-intercepts if they exist.
- y=2x2−4x−6
- y=−x2+4x−4
- y=4x2−9
- y=x2+2x−1
- Determine the maximum or minimum y-value: y=−3x2+12x−15.
- Determine the x- and y-intercepts: y=x2+x+4.
- Determine the domain and range: y=25x2−10x+1.
- The height in feet reached by a model rocket launched from a platform is given by the function h(t)=−16t2+256t+3, where t represents time in seconds after launch. What is the maximum height attained by the rocket.
- A bicycle manufacturing company has determined that the weekly revenue in dollars can be modeled by the formula R=200n−n2, where n represents the number of bicycles produced and sold. How many bicycles does the company have to produce and sell in order to maximize revenue?
- Rewrite in terms of i: √−60.
- Divide: 4−2i4+2i.
- Answer
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1.
Figure 9.E.5 3.
Figure 9.E.6 5. Maximum: y=−3
7. Domain: R; range: [0,∞)
9. To maximize revenue, the company needs to produce and sell 100 bicycles a week.
11. 35−i45
Solve.
- 25x2+3=0
- −2x2+5x−1=0
- Answer
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2. 5±√174