Bài 1:
d: \(\frac{3\cdot13-13\cdot18}{15\cdot40-80}\)
\(=\frac{13\left(3-18\right)}{40\left(15-2\right)}=\frac{13\cdot\left(-15\right)}{40\cdot13}=-\frac{15}{40}=-\frac38\)
h: \(\left\lbrack6+\left(\frac12\right)^3-\frac12\right\rbrack:\frac{3}{12}=\left\lbrack6+\frac18-\frac12\right\rbrack\cdot4\)
\(=\left(\frac{49}{8}-\frac48\right)\cdot4=\frac{45}{8}\cdot4=\frac{45}{2}\)
m: \(\frac{-3}{7}:\frac{11}{5}+\frac{-3}{7}:\frac{11}{6}+\frac{\left(-3\right)^2}{7}\)
\(=-\frac37\cdot\left(\frac{5}{11}+\frac{6}{11}\right)+\frac97\)
\(=-\frac37+\frac97=\frac67\)
Bài 3:
e: \(\left|\frac23x-\frac{-3}{5}\right|+2\frac12=\frac38\)
=>\(\left|\frac23x+\frac35\right|=\frac38-\frac52=\frac38-\frac{20}{8}=-\frac{17}{8}<0\) (vô lý)
=>x∈∅
i: ĐKXĐ: x<>-1/3
\(\frac{3x+1}{16}=\frac{4}{3x+1}\)
=>\(\left(3x+1\right)^2=4\cdot16=64\)
=>\(\left[\begin{array}{l}3x+1=8\\ 3x+1=-8\end{array}\right.\Rightarrow\left[\begin{array}{l}3x=7\\ 3x=-9\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac73\\ x=-3\end{array}\right.\)
f: \(2\frac13-\left|\frac23-x\right|=75\%\)
=>\(\frac73-\left|x-\frac23\right|=\frac34\)
=>\(\left|x-\frac23\right|=\frac73-\frac34=\frac{28-9}{12}=\frac{19}{12}\)
=>\(\left[\begin{array}{l}x-\frac23=\frac{19}{12}\\ x-\frac23=-\frac{19}{12}\end{array}\right.\Rightarrow\left[\begin{array}{l}x=\frac{19}{12}+\frac23=\frac{19}{12}+\frac{8}{12}=\frac{27}{12}=\frac94\\ x=-\frac{19}{12}+\frac23=-\frac{11}{12}\end{array}\right.\)
k: \(\left(1-2x\right)^2+\left(65\%\cdot x-26\right)^2=0\)
=>\(\begin{cases}1-2x=0\\ 0,65x-26=0\end{cases}\Rightarrow x\in\) ∅
g: \(\left(x+\frac13\right)^2-2\frac13=\frac{20}{3}\)
=>\(\left(x+\frac13\right)^2=\frac{20}{3}+2+\frac13=7+2=9\)
=>\(\left[\begin{array}{l}x+\frac13=3\\ x+\frac13=-3\end{array}\right.\Rightarrow\left[\begin{array}{l}x=3-\frac13=\frac83\\ x=-3-\frac13=-\frac{10}{3}\end{array}\right.\)
l: \(60\%\cdot x+\frac23x=\frac13\cdot6\frac13\)
=>\(x\left(\frac35+\frac23\right)=\frac13\cdot\frac{19}{3}=\frac{19}{9}\)
=>\(x\cdot\frac{19}{15}=\frac{19}{9}\)
=>\(x=\frac{19}{9}:\frac{19}{15}=\frac{15}{9}=\frac53\)
