| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 | 
| Correct | 0 | 3.22 | 
| Score | 0% | 64% | 
Find the value of a:
 6a + x = -5
 -a - 2x = 4
| -2\(\frac{11}{14}\) | |
| 2\(\frac{2}{23}\) | |
| 1\(\frac{3}{7}\) | |
| -\(\frac{6}{11}\) | 
You need to find the value of a so solve the first equation in terms of x:
 6a + x = -5 
 x = -5 - 6a 
then substitute the result (-5 - 6a) into the second equation:
 -a - 2(-5 - 6a) = 4 
 -a + (-2 x -5) + (-2 x -6a) = 4 
 -a + 10 + 12a = 4 
 -a + 12a = 4 - 10 
 11a = -6 
 a = \( \frac{-6}{11} \) 
 a = -\(\frac{6}{11}\) 
The formula for the area of a circle is which of the following?
| a = π d2 | |
| a = π r2 | |
| a = π d | |
| 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.
The endpoints of this line segment are at (-2, 5) and (2, 1). What is the slope of this line?
| -3 | |
| -1 | |
| 1 | |
| -2 | 
The slope of this line is the change in y divided by the change in x. The endpoints of this line segment are at (-2, 5) and (2, 1) so the slope becomes:
m = \( \frac{\Delta y}{\Delta x} \) = \( \frac{(1.0) - (5.0)}{(2) - (-2)} \) = \( \frac{-4}{4} \)If the area of this square is 4, what is the length of one of the diagonals?
| 7\( \sqrt{2} \) | |
| 8\( \sqrt{2} \) | |
| 6\( \sqrt{2} \) | |
| 2\( \sqrt{2} \) | 
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 = \( \sqrt{a} \) = \( \sqrt{4} \) = 2
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 = 22 + 22
 c2 = 8
 c = \( \sqrt{8} \) = \( \sqrt{4 x 2} \) = \( \sqrt{4} \) \( \sqrt{2} \)
 c = 2\( \sqrt{2} \) 
Simplify 9a x 7b.
| 63\( \frac{a}{b} \) | |
| 63\( \frac{b}{a} \) | |
| 63a2b2 | |
| 63ab | 
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.
9a x 7b = (9 x 7) (a x b) = 63ab