Question

${3}^{y + 1} + {3}^{y - 1} = 90 \: find \: value \: of \: y$

find value of y.​

Answer 1

Answer:

y = 3

Step by Step explanation:

{3}^{y + 1} + {3}^{y - 1} = 90

(3^y . 3) + (3^y / 3) = 90

3^y (3 + 1/3) = 90

3^y (10/3) = 90

3^y = 90 × 3/10

3^y = 27

3^y = 3^3

y = 3