EXPONENTIALS 2

If (2^x-17)(7^y+8) = (2²⁰)(7²⁸) find 2x+y.

solution

2^x-17 = 2²⁰

x – 17 = 20

x = 20+17

x = 37

…………………………

7^y+8 = 7²⁸

y + 8 = 28

y = 28 - 8

y = 20

……………………

2x + y = 2(37) + 20 = 74 + 20=94.

TRY THIS………….

 NECTA F-IV,2008 QN. 3a

If (2^x-7)(7^y+8) = (2²⁰)(7²⁸) find (i)x+y.      (ii) y/x