Question

How do you solve `87= 39+ r`?

Answer 1

To find an unknown work backwards `r = 48`

Explanation:

`87 = 39 + r`

The opposite of + 39 is - 39 so subtract 39 from both sides

`87 color(red)(-39) = 39 color(red)(-39) + r`

`87-39=0+r`

This results in

`48 = r`