Download 8.7 Practice C Solving Quadratic Equations by Using Square Roots

8.7 Practice C
Solving Quadratic Equations by Using Square Roots
Solve using square roots.
1. x2  81
2. 49  x 2
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4. x 2  225
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7. 49  x
2
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10. x  121 0
2
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13. 9x2  144
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5. 144  x2
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8. 2x  72
2
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11. 2x  10  22
2
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14. 0  8x2  72
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3. x 2  36
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6. x 2  169
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9. 10x 2  1000  0
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12. 15x2  60  15
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15. 250  9x2  25
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Solve. Round to the nearest hundredth.
16. 8x 2  40
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19. 5x2  175  450
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17. 0  x2  76
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20. 3  14  x 2
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18. 114  3x2  0
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21. 8.2x2  24.6  0
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22. The area of a square is 40 in2. If the length of each
side of the square is 2x in., what is the value of x?
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23. A room is shaped like a trapezoid. The distance between the
parallel walls is x. The length of one of these walls is 3 less
than x, and the length of the other is 3 more than x. The area
of the room’s floor is 354 ft2. Find the distance between the
parallel walls to the nearest tenth of a foot.
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24. A square with side length a, and a triangle whose base and
height both have length b, have the same area. Write an
equation for b in terms of a.
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