Hey there!
[tex]\bold{u^2=81}[/tex]
Take your SQUARE ROOT
[tex]\bold{New\ equation: x\pm \sqrt{81}}\\ \\ \bold{\sqrt{81}=9}\\ \\ \bold{-\sqrt{-81}=-9}\\ \\ \\ \\ \boxed{\boxed{\bold{Answer: x=-9\ or\ x =9}}}\huge\checkmark[/tex]
Good luck on your assignment and enjoy your day!
~[tex]\frak{LoveYourselfFirst:)}[/tex]
