Answer:
3.5
Explanation:
So the average of numbers can be defined as:

In other words, (the sum of numbers) / (the amount of numbers)
In our case, there is 7 numbers. The sum can be written as:

Adding like terms we get:

Now combing the sum and amount we get the fraction:

Since we're given the average, we can set that equal to our expression to solve for x:

No all we do is use some basic algebraic properties
Original Equation:

Multiply both sides by 28

Subtract 28 from both sides

Divide both sides by 2x
