1)In the expansion of $\displaystyle (2x-3)^1^5$ if$\displaystyle 13T3 + 10T4 + T5 = 0$ where Tn is the term number n

find the values of X that satisfy the given

....My solution : x= 0.5 , 4.5 , 0

Guide answer : 0.5 , 4.5 only ???

2)If the ratio between the two middle terms in the expansion of $\displaystyle (1+x)^2^7$ is 1:4 find the value of X

My solution : x=4 or 0.25

Guide answer : 4 only ???