| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.17 |
| Score | 0% | 63% |
If \(\left|a\right| = 7\), which of the following best describes a?
a = -7 |
|
none of these is correct |
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a = 7 |
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a = 7 or a = -7 |
The absolute value is the positive magnitude of a particular number or variable and is indicated by two vertical lines: \(\left|-5\right| = 5\). In the case of a variable absolute value (\(\left|a\right| = 5\)) the value of a can be either positive or negative (a = -5 or a = 5).
What is \( 4 \)\( \sqrt{12} \) - \( 2 \)\( \sqrt{3} \)
| 2\( \sqrt{5} \) | |
| 2\( \sqrt{12} \) | |
| 8\( \sqrt{12} \) | |
| 6\( \sqrt{3} \) |
To subtract these radicals together their radicands must be the same:
4\( \sqrt{12} \) - 2\( \sqrt{3} \)
4\( \sqrt{4 \times 3} \) - 2\( \sqrt{3} \)
4\( \sqrt{2^2 \times 3} \) - 2\( \sqrt{3} \)
(4)(2)\( \sqrt{3} \) - 2\( \sqrt{3} \)
8\( \sqrt{3} \) - 2\( \sqrt{3} \)
Now that the radicands are identical, you can subtract them:
8\( \sqrt{3} \) - 2\( \sqrt{3} \)If a car travels 675 miles in 9 hours, what is the average speed?
| 65 mph | |
| 40 mph | |
| 75 mph | |
| 30 mph |
Average speed in miles per hour is the number of miles traveled divided by the number of hours:
speed = \( \frac{\text{distance}}{\text{time}} \)If a rectangle is twice as long as it is wide and has a perimeter of 18 meters, what is the area of the rectangle?
| 72 m2 | |
| 18 m2 | |
| 162 m2 | |
| 2 m2 |
The area of a rectangle is width (w) x height (h). In this problem we know that the rectangle is twice as long as it is wide so h = 2w. The perimeter of a rectangle is 2w + 2h and we know that the perimeter of this rectangle is 18 meters so the equation becomes: 2w + 2h = 18.
Putting these two equations together and solving for width (w):
2w + 2h = 18
w + h = \( \frac{18}{2} \)
w + h = 9
w = 9 - h
From the question we know that h = 2w so substituting 2w for h gives us:
w = 9 - 2w
3w = 9
w = \( \frac{9}{3} \)
w = 3
Since h = 2w that makes h = (2 x 3) = 6 and the area = h x w = 3 x 6 = 18 m2
What is the greatest common factor of 48 and 16?
| 14 | |
| 3 | |
| 16 | |
| 11 |
The factors of 48 are [1, 2, 3, 4, 6, 8, 12, 16, 24, 48] and the factors of 16 are [1, 2, 4, 8, 16]. They share 5 factors [1, 2, 4, 8, 16] making 16 the greatest factor 48 and 16 have in common.