Bài 1:
a: \(A=\left(-2\frac15+\frac27-\frac{12}{13}\right)-\left(-\frac57+\frac{1}{13}\right)\)
\(=-\frac{11}{5}+\frac27-\frac{12}{13}+\frac57-\frac{1}{13}\)
\(=-\frac{11}{5}+1-1=-\frac{11}{5}\)
b: \(B=\frac{12}{17}\cdot\frac57-\frac{-12}{17}\cdot\frac17+\frac{1}{17\cdot7}\cdot12\)
\(=\frac{12}{17}\left(\frac57+\frac17+\frac17\right)\)
\(=\frac{12}{17}\cdot1=\frac{12}{17}\)
c: \(C=\left(\frac13-2\frac16\right)^2:\left(-3\frac{13}{36}\right)\)
\(=\left(\frac13-\frac{13}{6}\right)^2:\left(-\frac{108}{36}-\frac{13}{36}\right)\)
\(=\left(-\frac{11}{6}\right)^2:\frac{-121}{36}=\frac{121}{36}\cdot\frac{36}{-121}=-1\)
Bài 2:
a: \(A=\left|\frac{1}{-5}\right|-\frac{\left(-2\right)^2}{\left|-5\right|}-\frac{\left|-2\right|}{5}=\frac15-\frac45-\frac25=\frac{1-6}{5}=-\frac55=-1\)
b: \(2^3+3\cdot\left(\frac19\right)^0-\frac{1}{2^2}\cdot4+\left\lbrack\left(-2\right)^2:\frac12\right\rbrack\cdot8\)
\(=8+3-\frac14\cdot4+4\cdot2\cdot8\)
=11+64-1
=10+64
=74
c: \(C=\left(-\frac23\right)^3\cdot\left(-\frac23\right)^2+\frac{2^{40}\cdot3^{29}}{8^{13}\cdot9^{15}}=-\frac23+\frac{2^{40}\cdot3^{29}}{2^{39}\cdot3^{30}}=-\frac23+\frac23=0\)
Bài 3:
a: (2x+1,4)(3x-1,5)=0
=>\(\left[\begin{array}{l}2x+1,4=0\\ 3x-1,5=0\end{array}\right.\Rightarrow\left[\begin{array}{l}2x=-1,4\\ 3x=1,5\end{array}\right.\Rightarrow\left[\begin{array}{l}x=-0,7\\ x=0,5\end{array}\right.\)
b: \(\frac{2x}{3}-\frac16x-\frac{x+4}{2}=0\)
=>\(\frac{4x}{6}-\frac{x}{6}-\frac{3\left(x+4\right)}{6}=0\)
=>3x-3(x+4)=0
=>-12=0(vô lý)
c: \(\frac{x+3}{5}=-\frac32\)
=>\(x+3=-5\cdot\frac32=-\frac{15}{2}\)
=>\(x=-\frac{15}{2}-3=-\frac{21}{2}\)
d: \(\frac{1-5x}{2}=\frac{13}{36}-\frac{x+1}{3}\)
=>18(1-5x)=13-12(x+1)
=>18-90x=13-12x-12
=>-90x+18=-12x+1
=>-72x=-17
=>\(x=\frac{17}{72}\)
