| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.17 |
| Score | 0% | 43% |
Factor y2 - 2y - 63
| (y - 9)(y + 7) | |
| (y + 9)(y - 7) | |
| (y + 9)(y + 7) | |
| (y - 9)(y - 7) |
To factor a quadratic expression, apply the FOIL method (First, Outside, Inside, Last) in reverse. First, find the two Last terms that will multiply to produce -63 as well and sum (Inside, Outside) to equal -2. For this problem, those two numbers are -9 and 7. Then, plug these into a set of binomials using the square root of the First variable (y2):
y2 - 2y - 63
y2 + (-9 + 7)y + (-9 x 7)
(y - 9)(y + 7)
Find the value of a:
-a + x = 3
-6a - 4x = -8
| -\(\frac{2}{5}\) | |
| -\(\frac{1}{13}\) | |
| -3\(\frac{16}{17}\) | |
| -17 |
You need to find the value of a so solve the first equation in terms of x:
-a + x = 3
x = 3 + a
then substitute the result (3 - -1a) into the second equation:
-6a - 4(3 + a) = -8
-6a + (-4 x 3) + (-4 x a) = -8
-6a - 12 - 4a = -8
-6a - 4a = -8 + 12
-10a = 4
a = \( \frac{4}{-10} \)
a = -\(\frac{2}{5}\)
The formula for the area of a circle is which of the following?
c = π d2 |
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c = π r2 |
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c = π d |
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c = π r |
The circumference of a circle is the distance around its perimeter and equals π (approx. 3.14159) x diameter: c = π d. The area of a circle is π x (radius)2 : a = π r2.
Which of the following is not required to define the slope-intercept equation for a line?
slope |
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x-intercept |
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y-intercept |
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\({\Delta y \over \Delta x}\) |
A line on the coordinate grid can be defined by a slope-intercept equation: y = mx + b. For a given value of x, the value of y can be determined given the slope (m) and y-intercept (b) of the line. The slope of a line is change in y over change in x, \({\Delta y \over \Delta x}\), and the y-intercept is the y-coordinate where the line crosses the vertical y-axis.
Solve for x:
3x + 5 < 8 - 2x
| x < -\(\frac{6}{7}\) | |
| x < \(\frac{3}{5}\) | |
| x < \(\frac{7}{8}\) | |
| x < 1\(\frac{2}{3}\) |
To solve this equation, repeatedly do the same thing to both sides of the equation until the variable is isolated on one side of the < sign and the answer on the other.
3x + 5 < 8 - 2x
3x < 8 - 2x - 5
3x + 2x < 8 - 5
5x < 3
x < \( \frac{3}{5} \)
x < \(\frac{3}{5}\)