Question

{[(3×y+5)×3+5]×3+5}×3+5=281

Answer 1

((9y+15+5)*3+5)*3+5=281
((9y+20)*3+5)*3+5=281
(27y+60+5)*3+5=281
(27y+65)*3+5=281
81y+195+5=281
81y+200=281
81y=281-200
81y=81
y=81/81
y=1

Answer 2

{[(3×y+5)×3+5]×3+5}×3+5=281
{[(3×y+5)×3+5]×3+5}×3=281-5
[(3×y+5)×3+5]×3+5=276:3
[(3×y+5)×3+5]×3=92-5
(3×y+5)×3+5=87:3
(3×y+5)×3=29-5
3×y+5=24:3
3×y=8-5
y=3:3
y=1