Answer:
10 ^(R-15)/3 -2= a
Explanation:
R = 3 log (a+2) +15
Subtract 15 from each side
R-15 = 3 log (a+2) +15-15
R-15 = 3 log (a+2)
Divide each side by 3
(R-15)/3 = 3/3 log (a+2)
(R-15)/3 = log (a+2)
The opposite of log is to raise each side to the power of 10
10 ^(R-15)/3 = 10 ^ log (a+2)
10 ^(R-15)/3 = (a+2)
Subtract 2 from each side
10 ^(R-15)/3 -2= (a+2-2)
10 ^(R-15)/3 -2= a