In order to get the average of a list on numbers, we have to take the sum of all the numbers and divide them to how many they are.
Making that statement an equation, we do:
[tex] \frac{2+4x+6+8+10}{5}=x [/tex]
Notice that we divide it by 5 because we have 5 numbers. We equate it by x because the problem says that it should be the average.
Divide both sides by 5,
[tex]2+4x+6+8+10=5x[/tex]
Combine all the constants,
[tex]4x+26=5x[/tex]
Transpose,
[tex]26=x[/tex]
Therefore, we get 26 as x.
In order to check if we got the right answer, substitute 26 on x and see if you get an equation.
Hope that helps.
