Giải thích các bước giải:
a) `6 ×8^x-1+8^x+1=6 ×8^19+8^21`
`=>7×8^x=8^19×(6+8^2)`
`=>7xx8^x=8^19xx70`
`=>7xx8^x-8^19xx70=0`
`=>8^x-8^19xx10=0`
`=>8^x-8^x xx8^(19-x) xx10=0`
`=>8^x xx(1-8^(19-x)xx10)=0`
`=>`\(\left[ \begin{array}{l}8^x=0\\10×8^{19-x}=\text{1 (vì x∉N*)}\end{array} \right.\) `=>8^x=0=>x=1`
Vậy `x=1.`
b) `(4^5+4^5+4^5)/(3^5+3^5+3^5) ×(6^5+6^5+6^5+6^5+6^5+6^5)/(2^5+2^5)=2^x`
`=>(3xx4^5)/(3xx3^5) ×(6xx6^5)/(2xx2^5)=2^x`
`=>(4/3)^5×6^6/2^6=2^x`
`=>(4/3)^5×6^6/2^6=2^x`
`=>(4/3)^5×3^6=2^x`
`=>(4/3)^5×3^5xx3=2^x`
`=>4^5xx3=2^x`
`=>1024=2^x`
`=>x=10`
