if a= nc2then prove that ac2 = 3 × n+1c4

With the value of a in terms of n, substitute the LHS of^ac₂= 3×ⁿ⁺¹c4

Get the eqn in terms of just n as variable. Multiply and divide by 3 to obtain the factorial in the denominator as well as a 3 in the numerator as a multiplicand. Factorise the degree 4 eqn with
(n+1) as the known factor(...From ⁿ⁺¹c₄)

Get the value by obtaining the factors. and putting it in factorial form