x^2n-1+y^2n-1 is divisible by x+y if n is

If (1+x+x²)ⁿ = a₀+a₁x+a₂x²+……..+a_2nx²ⁿ then a₀²-a₁²+a₂²-……….+a_2n² =

⁽²ⁿ⁺¹⁾C₀-⁽²ⁿ⁺¹⁾C₁+…………. -⁽²ⁿ⁺¹⁾C_2n =

The coefficient of x² in (1+x)²(8-x)^-1/3 is

C₀²+3.C₁²+5.C₂²+……….+(2n+1).C_n² =

1.ⁿC₀+4¹.ⁿC₁+4².ⁿC₂+4³.ⁿC₃+……..+4ⁿ.ⁿC_n =

3.C₀+7.C₁+11.C₂+……..+(4n+3).C_n =

(1.02)⁶ + (0.98)⁶ =

(2-)⁵ + (2+)⁵ =

If the 3^rd, 4^th and 5^th terms of (x+a)ⁿ are 60, 160 and 240 respectively then (x,a,n)=