The coefficient of the middle term in the binomial expansion of (1 + ax)4 and of (1 – ax)6 6 is the same is a equals

Middle term in the expansion of (1+ax)4 is  4C2(αx)2=6α2x2 and the middle term in the expansion of  (1−αx)6 is  6C3(−αx)3=−20α3x3.We are given 6α2=−20α3⇒α=0 or α=−310