Your Results | Global Average | |
---|---|---|
Questions | 5 | 5 |
Correct | 0 | 3.11 |
Score | 0% | 62% |
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 or a = -7 |
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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).
If a rectangle is twice as long as it is wide and has a perimeter of 54 meters, what is the area of the rectangle?
50 m2 | |
2 m2 | |
162 m2 | |
72 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 54 meters so the equation becomes: 2w + 2h = 54.
Putting these two equations together and solving for width (w):
2w + 2h = 54
w + h = \( \frac{54}{2} \)
w + h = 27
w = 27 - h
From the question we know that h = 2w so substituting 2w for h gives us:
w = 27 - 2w
3w = 27
w = \( \frac{27}{3} \)
w = 9
Since h = 2w that makes h = (2 x 9) = 18 and the area = h x w = 9 x 18 = 162 m2
If \( \left|b + 3\right| \) - 2 = 1, which of these is a possible value for b?
-8 | |
18 | |
-2 | |
0 |
First, solve for \( \left|b + 3\right| \):
\( \left|b + 3\right| \) - 2 = 1
\( \left|b + 3\right| \) = 1 + 2
\( \left|b + 3\right| \) = 3
The value inside the absolute value brackets can be either positive or negative so (b + 3) must equal + 3 or -3 for \( \left|b + 3\right| \) to equal 3:
b + 3 = 3 b = 3 - 3 b = 0 | b + 3 = -3 b = -3 - 3 b = -6 |
So, b = -6 or b = 0.
What is \( \frac{27\sqrt{16}}{9\sqrt{4}} \)?
\(\frac{1}{4}\) \( \sqrt{3} \) | |
4 \( \sqrt{3} \) | |
\(\frac{1}{3}\) \( \sqrt{\frac{1}{4}} \) | |
3 \( \sqrt{4} \) |
To divide terms with radicals, divide the coefficients and radicands separately:
\( \frac{27\sqrt{16}}{9\sqrt{4}} \)
\( \frac{27}{9} \) \( \sqrt{\frac{16}{4}} \)
3 \( \sqrt{4} \)
Simplify \( \sqrt{45} \)
9\( \sqrt{5} \) | |
3\( \sqrt{10} \) | |
2\( \sqrt{10} \) | |
3\( \sqrt{5} \) |
To simplify a radical, factor out the perfect squares:
\( \sqrt{45} \)
\( \sqrt{9 \times 5} \)
\( \sqrt{3^2 \times 5} \)
3\( \sqrt{5} \)