Simplifying index equation

[Ocean]

Hello, I was wondering if you could help me with this question. The answer is 4/21 but I can’t seem to get to it.

Simplify [7^(2x+1) - 7^(2x-1) - 48] / [36 * 7^(2x) - 252]

 

[Steven G]

Hint: 7^a+b=7^a7^b and note that (2x+1) = 2+ (2x-1)

 

[Steven G]

7^(2x+1)- 7^(2x-1) - 48 = 7^(2x-1)( 49 -1) - 48 = 48( 7^(2x-1) - 1) = 48( 49^x * 7^-1 - 1)

36 * 7^2x - 252 = 36*7^2x - 36*7 = 36(49^x-7)

What you see above should be very helpful.