`1l)` `{81^{11}. 3^{17}}/{27^{10}. 9^{15}}`
`={(3^4)^{11}.3^{17}}/{(3^3)^{10}.(3^2)^{15}}`
`={3^{44}. 3^{17}}/{3^{30}. 3^{30}}`
`={3^{61}}/{3^{60}}=3`
$\\$
`2a)` `4\ 5/{27}+7/{23}+0,5. 5/{27}+{16}/{23}+5/{27}`
`=4+ (5/{27}+0, 5 . 5/{27}+5/{27})+ (7/{23}+{16}/{23})`
`=4+5/{27}. (1+0,5+1)+1`
`=4+5/{27}. 5/ 2 +1`
`=5+{25}/{54}={295}/{54}`
$\\$
`3c)` `(7/9)^6:({-7}/9)^4`
`=(7/9)^6:(7/9)^4=(7/9)^2={7^2}/{9^2}={49}/{81}`
$\\$
`d)` `(2/ 3)^6:(4/9)^3`
`=(2/ 3)^6 : [(2/ 3 )^2]^3`
`=(2/ 3)^3={2^3}/{3^3}=8/{27}`
$\\$
`g)` `(-8)^4:(-4)^4`
`=({-8}/{-4})^4=2^4=16`
$\\$
`4_3)` `x^2+x=0`
`=>x(x+1)=0`
`=>`$\left[\begin{array}{l}x=0\\x+1=0\end{array}\right.$`=>`$\left[\begin{array}{l}x=0\\x=-1\end{array}\right.$
Vậy `x=0` hoặc `x=-1`
$\\$
`4_8)` `({-3}/4)^{3x-1}=9/{16}`
`=>({-3}/4)^{3x-1}=({-3}/4)^2`
`=>3x-1=2`
`=>3x=2+1`
`=>3x=3`
`=>x=3:3`
`=>x=1`
Vậy `x=1`
