Đáp án + Giải thích các bước giải:
Ta có :
`a,\frac{1}{4}x+\frac{5}{9}=\frac{1}{3}`
`→\frac{1}{4}x=-\frac{2}{9}`
`→x=-\frac{8}{9}`
`b,\frac{3}{4}-(x-\frac{2}{5})=\frac{11}{12}`
`→x-\frac{2}{5}=-\frac{1}{6}`
`→x=\frac{7}{30}`
`c,|x+\frac{1}{3}|+1=4`
`→|x+\frac{1}{3}|=3`
`→` \(\left[ \begin{array}{l}x+\frac{1}{3}=3\\x+\frac{1}{3}=-3\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=\frac{8}{3}\\x=-\frac{10}{3}\end{array} \right.\)
Vậy `x∈{\frac{8}{3};-\frac{10}{3}}`
`d,27^x=3^{x+2}`
`→(3^3)^x=3^{x+2}`
`→3^{3x}=3^{x+2}`
`→3x=x+2`
`→3x-x=2`
`→2x=2`
`→x=1`
