| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 2.92 |
| Score | 0% | 58% |
If b = 7 and x = -2, what is the value of -2b(b - x)?
| 24 | |
| -126 | |
| 1008 | |
| 252 |
To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)
-2b(b - x)
-2(7)(7 + 2)
-2(7)(9)
(-14)(9)
-126
Which types of triangles will always have at least two sides of equal length?
equilateral, isosceles and right |
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equilateral and isosceles |
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isosceles and right |
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equilateral and right |
An isosceles triangle has two sides of equal length. An equilateral triangle has three sides of equal length. In a right triangle, two sides meet at a right angle.
If the base of this triangle is 4 and the height is 6, what is the area?
| 12\(\frac{1}{2}\) | |
| 12 | |
| 63 | |
| 84\(\frac{1}{2}\) |
The area of a triangle is equal to ½ base x height:
a = ½bh
a = ½ x 4 x 6 = \( \frac{24}{2} \) = 12
When two lines intersect, adjacent angles are __________ (they add up to 180°) and angles across from either other are __________ (they're equal).
acute, obtuse |
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supplementary, vertical |
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obtuse, acute |
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vertical, supplementary |
Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are supplementary (they add up to 180°) and angles across from either other are vertical (they're equal).
Solve for a:
a2 + 7a - 64 = 5a - 1
| 7 or -9 | |
| 5 or -3 | |
| -5 or -8 | |
| 3 or 3 |
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 - 64 = 5a - 1
a2 + 7a - 64 + 1 = 5a
a2 + 7a - 5a - 63 = 0
a2 + 2a - 63 = 0
Next, factor the quadratic equation:
a2 + 2a - 63 = 0
(a - 7)(a + 9) = 0
For this expression to be true, the left side of the expression must equal zero. Therefore, either (a - 7) or (a + 9) must equal zero:
If (a - 7) = 0, a must equal 7
If (a + 9) = 0, a must equal -9
So the solution is that a = 7 or -9