First you need to open the parentheses and distribute 6 to the contents:
8x²=36+60=96, now divide both sides by 8: x²=12. Or you could just add 10 and 6 to make 16 then multiply by 6 to get 96, then divide both sides by 8.
The square root of 12=√4×3=2√3.
And -2√3 is also a solution. 2√3 evaluates to about 3.464.