| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.00 |
| Score | 0% | 60% |
Find the value of a:
-2a + y = -4
-3a + 9y = -1
| -\(\frac{3}{4}\) | |
| \(\frac{4}{17}\) | |
| 1 | |
| 2\(\frac{1}{3}\) |
You need to find the value of a so solve the first equation in terms of y:
-2a + y = -4
y = -4 + 2a
then substitute the result (-4 - -2a) into the second equation:
-3a + 9(-4 + 2a) = -1
-3a + (9 x -4) + (9 x 2a) = -1
-3a - 36 + 18a = -1
-3a + 18a = -1 + 36
15a = 35
a = \( \frac{35}{15} \)
a = 2\(\frac{1}{3}\)
If BD = 9 and AD = 12, AB = ?
| 12 | |
| 20 | |
| 3 | |
| 4 |
The entire length of this line is represented by AD which is AB + BD:
AD = AB + BD
Solving for AB:AB = AD - BDWhat is 8a4 + 4a4?
| 12a4 | |
| 4 | |
| 12 | |
| 32a4 |
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.
8a4 + 4a4 = 12a4
If b = 5 and y = -8, what is the value of -8b(b - y)?
| -40 | |
| -60 | |
| -520 | |
| 60 |
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.)
-8b(b - y)
-8(5)(5 + 8)
-8(5)(13)
(-40)(13)
-520
Solve 7a - 7a = -3a - 3y - 6 for a in terms of y.
| -2\(\frac{1}{4}\)y + \(\frac{1}{4}\) | |
| \(\frac{1}{2}\)y - 1\(\frac{1}{4}\) | |
| \(\frac{2}{5}\)y - \(\frac{3}{5}\) | |
| -1\(\frac{2}{3}\)y + \(\frac{2}{3}\) |
To solve this equation, isolate the variable for which you are solving (a) on one side of the equation and put everything else on the other side.
7a - 7y = -3a - 3y - 6
7a = -3a - 3y - 6 + 7y
7a + 3a = -3y - 6 + 7y
10a = 4y - 6
a = \( \frac{4y - 6}{10} \)
a = \( \frac{4y}{10} \) + \( \frac{-6}{10} \)
a = \(\frac{2}{5}\)y - \(\frac{3}{5}\)