Hi,
Again, we're going to be following the same format we did last time, but the sides of the equation have been swapped. Let's not worry about this, as it doesn't exactly make a difference.
Since 1 is negative, we must add it on both sides.
8 + 1 = 3r - 1 + 1
9 = 3r
Now, we have 3 which is multiplying our variable r. The inverse of multiplication is division, so we will divide both sides by 3. This will leave us with our answer.
9 / 3 = 3r / 3
3 = r or r = 3.
Hopefully, this helps.
