Answer:
r = 95
Step-by-step explanation:
log (r - 5) - 7 = -5 becomes log (r - 5) = 2. You had that right.
Now raise the base 10 to the power 'log (r - 5)' and equate that to the base 10 to the power 2:
log (r - 5) 2
10 = 10
Then r - 5 = 100, and r = 100 - 5 = 95. r = 95
