penyelesaian atau persamaan (2y+5)²-81=0

(2y+5)²-81 =0
(2y+5)²-9² =0
(2y+5+9) =0
2y = -14
y =- 14/2
y = -7
(2y+5-9)= 0
2y = 4
y =4/2
=2