#1**+2 **

y = 2 + √ [ y^2 - 12 ] subtract 2 from both sides

y - 2 = √ [y^2 - 12 ] square both sides

( y - 2)^2 = y^2 - 12

y^2 - 4y + 4 = y^2 - 12 subtract y^2 from both sides

-4y + 4 = -12 subtract 4 from both sides

-4y = -16 divide both sides by -4

y = 4

Check that this solution works in the original equation, GM....

CPhill Feb 25, 2019