
Divide by 3 on both sides:

Square root both sides:

Take away 3 from both sides:

Divide by 2 on both sides:

Answer:
You’re going to need to add a picture to the problem it cannot be solved with just this information
I hope you understood....if not...comment and I will be willing to still help
90% = 90/100 = 9/10 = 0.9
Hope this helps :)