| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.38 |
| Score | 0% | 68% |
Which of the following statements about math operations is incorrect?
you can multiply monomials that have different variables and different exponents |
|
you can add monomials that have the same variable and the same exponent |
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you can subtract monomials that have the same variable and the same exponent |
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all of these statements are correct |
You can only add or subtract monomials that have the same variable and the same exponent. For example, 2a + 4a = 6a and 4a2 - a2 = 3a2 but 2a + 4b and 7a - 3b cannot be combined. However, you can multiply and divide monomials with unlike terms. For example, 2a x 6b = 12ab.
What is the circumference of a circle with a diameter of 14?
| 15π | |
| 32π | |
| 14π | |
| 4π |
The formula for circumference is circle diameter x π:
c = πd
c = 14π
If side a = 8, side b = 9, what is the length of the hypotenuse of this right triangle?
| \( \sqrt{145} \) | |
| \( \sqrt{13} \) | |
| \( \sqrt{97} \) | |
| \( \sqrt{68} \) |
According to the Pythagorean theorem, the hypotenuse squared is equal to the sum of the two perpendicular sides squared:
c2 = a2 + b2
c2 = 82 + 92
c2 = 64 + 81
c2 = 145
c = \( \sqrt{145} \)
The dimensions of this cube are height (h) = 3, length (l) = 4, and width (w) = 4. What is the surface area?
| 142 | |
| 72 | |
| 112 | |
| 80 |
The surface area of a cube is (2 x length x width) + (2 x width x height) + (2 x length x height):
sa = 2lw + 2wh + 2lh
sa = (2 x 4 x 4) + (2 x 4 x 3) + (2 x 4 x 3)
sa = (32) + (24) + (24)
sa = 80
What is 7a + 9a?
| a2 | |
| -2a2 | |
| -2 | |
| 16a |
To combine like terms, add or subtract the coefficients (the numbers that come before the variables) of terms that have the same variable raised to the same exponent.
7a + 9a = 16a