The value of x for which the sixth term in the expansion of 2log2⁡9x−1+7+1215log2⁡3x−1+17 is 84 is

By the given condition,84=T6=T5+1=7C52log29x−1+721215log23x−1+15=21×2log29x−1+72−log23x−1+1or 4=2log2⁡9x−1+73x−1+1=9x−1+73x−1+1or 3x−12−4×3x−1+3=0or 3x−1−13x−1−3=0⇒3x−1=1 or 3⇒3x−1=30 or 31⇒x−1=0 or 1⇒x=1, 2