| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.40 |
| Score | 0% | 68% |
What is the area of a circle with a radius of 2?
| 25π | |
| 4π | |
| 64π | |
| 9π |
The formula for area is πr2:
a = πr2
a = π(22)
a = 4π
If a = 5, b = 7, c = 5, and d = 9, what is the perimeter of this quadrilateral?
| 13 | |
| 18 | |
| 26 | |
| 28 |
Perimeter is equal to the sum of the four sides:
p = a + b + c + d
p = 5 + 7 + 5 + 9
p = 26
A(n) __________ is two expressions separated by an equal sign.
equation |
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problem |
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formula |
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expression |
An equation is two expressions separated by an equal sign. The key to solving equations is to repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the equal sign and the answer on the other.
The endpoints of this line segment are at (-2, 6) and (2, -2). What is the slope-intercept equation for this line?
| y = -2x + 2 | |
| y = 2\(\frac{1}{2}\)x + 2 | |
| y = -1\(\frac{1}{2}\)x + 4 | |
| y = -\(\frac{1}{2}\)x - 2 |
The slope-intercept equation for a line is y = mx + b where m is the slope and b is the y-intercept of the line. From the graph, you can see that the y-intercept (the y-value from the point where the line crosses the y-axis) is 2. The slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, 6) and (2, -2) so the slope becomes:
m = \( \frac{\Delta y}{\Delta x} \) = \( \frac{(-2.0) - (6.0)}{(2) - (-2)} \) = \( \frac{-8}{4} \)Plugging these values into the slope-intercept equation:
y = -2x + 2
Simplify (7a)(4ab) + (6a2)(8b).
| 154ab2 | |
| 76a2b | |
| 20ab2 | |
| -20a2b |
To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.
(7a)(4ab) + (6a2)(8b)
(7 x 4)(a x a x b) + (6 x 8)(a2 x b)
(28)(a1+1 x b) + (48)(a2b)
28a2b + 48a2b
76a2b