$$\\81=6^x+2x-8x\\
81=6^x-6x\\$$
https://www.desmos.com/calculator/xcnbodzoi0
From my graph the approximate answers are x=-13.5 and x=2.55
$$\\81=6^x+2x-8x\\
81=6^x-6x\\$$
https://www.desmos.com/calculator/xcnbodzoi0
From my graph the approximate answers are x=-13.5 and x=2.55