<span>Say the code only needed to be one number long. Going from 0-9, there are ten digits. Therefore, there are ten unique codes.
Now say the code has to be two numbers long. There are ten possibilities
for the first digit, 0-9. But the second digit only has nine
possibilities, since each number has to be different. (The first number
might be 0, so the second can only go from 1-9) For each of the first
ten possibilities, there are nine possibilities for the second. We
multiply those two numbers together, 10 * 9, and we get 90.
Now we just extend the logic. The third number only has eight
possibilities, while the fourth number only has seven. 10 * 9 * 8 * 7 =
5040 possible codes. I hope this helped! has a great day! :)</span>
$9.47
I just multiplied the total by the refund percentage to get that number. It’s just like finding a tip.
Simplifying
9 + -2x = 35
Solving
9 + -2x = 35
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '-9' to each side of the equation.
9 + -9 + -2x = 35 + -9
Combine like terms: 9 + -9 = 0
0 + -2x = 35 + -9
-2x = 35 + -9
Combine like terms: 35 + -9 = 26
-2x = 26
Divide each side by '-2'.
x = -13
Simplifying
x = -13
