| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.13 |
| Score | 0% | 63% |
Solve for b:
b2 - 8b + 38 = 5b + 2
| 3 or -8 | |
| 7 or -2 | |
| 7 or 5 | |
| 4 or 9 |
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:
b2 - 8b + 38 = 5b + 2
b2 - 8b + 38 - 2 = 5b
b2 - 8b - 5b + 36 = 0
b2 - 13b + 36 = 0
Next, factor the quadratic equation:
b2 - 13b + 36 = 0
(b - 4)(b - 9) = 0
For this expression to be true, the left side of the expression must equal zero. Therefore, either (b - 4) or (b - 9) must equal zero:
If (b - 4) = 0, b must equal 4
If (b - 9) = 0, b must equal 9
So the solution is that b = 4 or 9
Simplify (8a)(7ab) + (8a2)(8b).
| 120ab2 | |
| 8ab2 | |
| 120a2b | |
| -8ab2 |
To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.
(8a)(7ab) + (8a2)(8b)
(8 x 7)(a x a x b) + (8 x 8)(a2 x b)
(56)(a1+1 x b) + (64)(a2b)
56a2b + 64a2b
120a2b
If angle a = 63° and angle b = 44° what is the length of angle d?
| 129° | |
| 117° | |
| 139° | |
| 124° |
An exterior angle of a triangle is equal to the sum of the two interior angles that are opposite:
d° = b° + c°
To find angle c, remember that the sum of the interior angles of a triangle is 180°:
180° = a° + b° + c°
c° = 180° - a° - b°
c° = 180° - 63° - 44° = 73°
So, d° = 44° + 73° = 117°
A shortcut to get this answer is to remember that angles around a line add up to 180°:
a° + d° = 180°
d° = 180° - a°
d° = 180° - 63° = 117°
If the area of this square is 16, what is the length of one of the diagonals?
| 4\( \sqrt{2} \) | |
| 7\( \sqrt{2} \) | |
| 5\( \sqrt{2} \) | |
| 8\( \sqrt{2} \) |
To find the diagonal we need to know the length of one of the square's sides. We know the area and the area of a square is the length of one side squared:
a = s2
so the length of one side of the square is:
s = \( \sqrt{a} \) = \( \sqrt{16} \) = 4
The Pythagorean theorem defines the square of the hypotenuse (diagonal) of a triangle with a right angle as the sum of the squares of the other two sides:
c2 = a2 + b2
c2 = 42 + 42
c2 = 32
c = \( \sqrt{32} \) = \( \sqrt{16 x 2} \) = \( \sqrt{16} \) \( \sqrt{2} \)
c = 4\( \sqrt{2} \)
If AD = 26 and BD = 18, AB = ?
| 2 | |
| 8 | |
| 4 | |
| 11 |
The entire length of this line is represented by AD which is AB + BD:
AD = AB + BD
Solving for AB:AB = AD - BD