8^(2x) = 4096
Note that 8 = 2^3 and 4096 = 2^12
So
(2^3)^(2x) = 2^12
2^(6x) = 2^12 solve for the exponents
6x = 12 divide both sides by 6
x = 2
We can use synthetic division here to find the remaining polynomial
3 [ 2 -9 11 - 6 ]
6 -9 6
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2 -3 2 0
So.....the remaining polynomial is 2x^2 - 3x + 2