Answer:
If your question is set up like this [tex]\sqrt{6x^2-8}=-8x[/tex] then your answer is No solution.
If your question is set up like this[tex]\sqrt{6x^2}-8=-8x[/tex] then your answer is [tex]x=\frac{4(8-\sqrt{6}) }{29}[/tex] or x = 0.765
Hope this helps!