Answer :
20n - 2 + 6.5 = 87
20n + 4.5 = 87
-4.5 -4.5
20n = 82.5
20 20
n = 4.125
or
20^n - 2 + 6.5 = 87
20^n + 4.5 = 87
-4.5 -4.5
20^n = 82.5
n ≈ 1.037
20n + 4.5 = 87
-4.5 -4.5
20n = 82.5
20 20
n = 4.125
or
20^n - 2 + 6.5 = 87
20^n + 4.5 = 87
-4.5 -4.5
20^n = 82.5
n ≈ 1.037