The coefficient of the middle term in the binomial expansion in powers of x of (1+αx)4 and of (1−αx)6 is the same if α equals
−310
Coefficient of Middle term in
(1+αx)4=t3=4C2.α2
Coefficient of Middle term in
(1−αx)6=t4=6C3.(−α)3
4C2α2=−6C3α3⇒−6=20α⇒α=−310