Answer :
answer is 11,-11
x²-121=0
x²- 11²=0
(x +11)(x-11) = 0
x + 11 = 0 then x = -11
x - 11 = 0 then x = 11
x²-121=0
x²- 11²=0
(x +11)(x-11) = 0
x + 11 = 0 then x = -11
x - 11 = 0 then x = 11