| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.15 |
| Score | 0% | 43% |
Which of the following is not required to define the slope-intercept equation for a line?
\({\Delta y \over \Delta x}\) |
|
slope |
|
y-intercept |
|
x-intercept |
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 5c + 2c = 4c + 3z + 3 for c in terms of z.
| -\(\frac{1}{3}\)z - 2\(\frac{1}{3}\) | |
| -2z + 1 | |
| -1\(\frac{1}{2}\)z - 2\(\frac{1}{4}\) | |
| z + 3 |
To solve this equation, isolate the variable for which you are solving (c) on one side of the equation and put everything else on the other side.
5c + 2z = 4c + 3z + 3
5c = 4c + 3z + 3 - 2z
5c - 4c = 3z + 3 - 2z
c = z + 3
Solve for x:
3x + 5 < \( \frac{x}{-4} \)
| x < \(\frac{8}{11}\) | |
| x < \(\frac{16}{55}\) | |
| x < \(\frac{5}{6}\) | |
| x < -1\(\frac{7}{13}\) |
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 < \( \frac{x}{-4} \)
-4 x (3x + 5) < x
(-4 x 3x) + (-4 x 5) < x
-12x - 20 < x
-12x - 20 - x < 0
-12x - x < 20
-13x < 20
x < \( \frac{20}{-13} \)
x < -1\(\frac{7}{13}\)
Solve for a:
a2 - 7a - 44 = -5a + 4
| 1 or -4 | |
| 5 or -5 | |
| -6 or 8 | |
| 2 or -4 |
The first step to solve a quadratic expression that's not set to zero is to solve the equation so that it is set to zero:
a2 - 7a - 44 = -5a + 4
a2 - 7a - 44 - 4 = -5a
a2 - 7a + 5a - 48 = 0
a2 - 2a - 48 = 0
Next, factor the quadratic equation:
a2 - 2a - 48 = 0
(a + 6)(a - 8) = 0
For this expression to be true, the left side of the expression must equal zero. Therefore, either (a + 6) or (a - 8) must equal zero:
If (a + 6) = 0, a must equal -6
If (a - 8) = 0, a must equal 8
So the solution is that a = -6 or 8
The dimensions of this cylinder are height (h) = 3 and radius (r) = 6. What is the surface area?
| 108π | |
| 132π | |
| 80π | |
| 156π |
The surface area of a cylinder is 2πr2 + 2πrh:
sa = 2πr2 + 2πrh
sa = 2π(62) + 2π(6 x 3)
sa = 2π(36) + 2π(18)
sa = (2 x 36)π + (2 x 18)π
sa = 72π + 36π
sa = 108π