| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.39 |
| Score | 0% | 68% |
Solve for y:
y2 + 2y - 16 = 3y - 4
| -1 or -9 | |
| -3 or 4 | |
| 9 or 6 | |
| 6 or -1 |
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:
y2 + 2y - 16 = 3y - 4
y2 + 2y - 16 + 4 = 3y
y2 + 2y - 3y - 12 = 0
y2 - y - 12 = 0
Next, factor the quadratic equation:
y2 - y - 12 = 0
(y + 3)(y - 4) = 0
For this expression to be true, the left side of the expression must equal zero. Therefore, either (y + 3) or (y - 4) must equal zero:
If (y + 3) = 0, y must equal -3
If (y - 4) = 0, y must equal 4
So the solution is that y = -3 or 4
Which of the following statements about math operations is incorrect?
you can multiply monomials that have different variables and different exponents |
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all of these statements are correct |
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you can subtract monomials that have the same variable and the same exponent |
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you can add monomials that have the same variable and the same exponent |
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.
The formula for the area of a circle is which of the following?
a = π d2 |
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a = π d |
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a = π r2 |
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a = 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.
A cylinder with a radius (r) and a height (h) has a surface area of:
π r2h2 |
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4π r2 |
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π r2h |
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2(π r2) + 2π rh |
A cylinder is a solid figure with straight parallel sides and a circular or oval cross section with a radius (r) and a height (h). The volume of a cylinder is π r2h and the surface area is 2(π r2) + 2π rh.
A right angle measures:
90° |
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45° |
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180° |
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360° |
A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.