8 - 5r / 6 = 3

Can you give me a quick refresher.

Scott

Hi Scott.

The notation 8 - 5r / 6 = 3 can be confusing. We do multiplication and division before addition and subtraction so I am reading this as

8 - ^5r/₆ = 3  

Just remember that when you are trying to solve an equation, whatever you do to one side you must do to the other.

Here's a similar question:

11 - 2y / 3 = 5

You want to isolate the variable (y in this case) on one side of the equation. Paying attention to the order of operations, we do this in steps:

subtract 11 from both sides:

11 - 2y / 3 - 11 = 5 - 11
-2y / 3 = -6

divide by -2 on both sides:

(-2y / 3) / (-2) = (-6) / (-2)
y / 3 = 3

now multiply by 3 on both sides to solve the problem:

3 ( y / 3) = 3 ( 3)
y = 9.

Last step is always to check your answer by putting the value in the original equation:

11 - 2y / 3 = 5
11 - 2(9) / 3 = 5
11 - 18 / 3 = 5
11 - 6 = 5
5 = 5.

Hope this example helps,
Stephen La Rocque