If you would like to solve the equation -5x - 25 = 78, you should do this using the following steps:
<span>-5x - 25 = 78
</span>-5x - 25 + 25 = 78 + 25
-5x + 0 = 103
-5x = 103 /(-5)
x = 103 / (-5)
x = - 103/5 = - 20.6
The error was already made at step 1.
The answer is 7 because the mean is an average. So if you add up all the numbers and then divide that number by the amount of numbers listed then that will get you your answer which is 7
4+5+6+7+8+9+10=49
49/7=7
Variables can be used to represent unknown numbers in a equation or expression that you will later find out what they are