| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.27 |
| Score | 0% | 65% |
What is 5z5 x 6z4?
| 30z-1 | |
| 30z5 | |
| 30z | |
| 30z9 |
To multiply terms with exponents, the base of both exponents must be the same. In this case they are so multiply the coefficients and add the exponents:
5z5 x 6z4
(5 x 6)z(5 + 4)
30z9
What is (a4)4?
| a0 | |
| 4a4 | |
| a8 | |
| a16 |
To raise a term with an exponent to another exponent, retain the base and multiply the exponents:
(a4)4The total water usage for a city is 10,000 gallons each day. Of that total, 10% is for personal use and 34% is for industrial use. How many more gallons of water each day is consumed for industrial use over personal use?
| 6,300 | |
| 2,400 | |
| 5,200 | |
| 8,250 |
34% of the water consumption is industrial use and 10% is personal use so (34% - 10%) = 24% more water is used for industrial purposes. 10,000 gallons are consumed daily so industry consumes \( \frac{24}{100} \) x 10,000 gallons = 2,400 gallons.
If \(\left|a\right| = 7\), which of the following best describes a?
a = 7 or a = -7 |
|
a = -7 |
|
none of these is correct |
|
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 12 meters, what is the area of the rectangle?
| 18 m2 | |
| 98 m2 | |
| 72 m2 | |
| 8 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 12 meters so the equation becomes: 2w + 2h = 12.
Putting these two equations together and solving for width (w):
2w + 2h = 12
w + h = \( \frac{12}{2} \)
w + h = 6
w = 6 - h
From the question we know that h = 2w so substituting 2w for h gives us:
w = 6 - 2w
3w = 6
w = \( \frac{6}{3} \)
w = 2
Since h = 2w that makes h = (2 x 2) = 4 and the area = h x w = 2 x 4 = 8 m2