a ) \(5.\left(x-7\right)=0\)
\(\Leftrightarrow x-7=5.0\)
\(\Leftrightarrow x-7=0\)
\(\Leftrightarrow x=7\)
b ) \(34.\left(2.x-6\right)=0\)
\(\Leftrightarrow2.x-6=34.0\)
\(\Leftrightarrow2.x-6=0\)
\(\Leftrightarrow2.x=0+6\)
\(\Leftrightarrow2.x=6\)
\(\Leftrightarrow x=6\div2\)
\(\Leftrightarrow x=3\)
c ) \(25+\left(15-x\right)=30\)
\(\Leftrightarrow25+\left(15-x\right)=-\left(x-40\right)\)
\(\Leftrightarrow-\left(x-40\right)=2.3.5\)
\(\Leftrightarrow40-x=30\)
\(\Leftrightarrow-x=-10\)
\(\Leftrightarrow x=10\)
d ) \(43-\left(24-x\right)=20\)
\(\Leftrightarrow24-x=43-20\)
\(\Leftrightarrow24-x=23\)
\(\Leftrightarrow x=24-23\)
\(\Leftrightarrow x=1\)
e ) \(2.\left(x-5\right)-17=25\)
\(\Leftrightarrow2.\left(x-5\right)=25+17\)
\(\Leftrightarrow2.\left(x-5\right)=42\)
\(\Leftrightarrow x-5=42\div2\)
\(\Leftrightarrow x-5=21\)
\(\Leftrightarrow x=21+5\)
\(\Leftrightarrow x=26\)
f ) \(24+3.\left(5-x\right)=27\)
\(\Leftrightarrow3.\left(5-x\right)=27-24\)'
\(\Leftrightarrow3.\left(5-x\right)=3\)
\(\Leftrightarrow5-x=3\div3\)
\(\Leftrightarrow5-x=1\)
\(\Leftrightarrow x=5-1\)
\(\Leftrightarrow x=4\)
g ) \(15\div x-2=3\)
\(\Leftrightarrow15\div x=3+2\)
\(\Leftrightarrow15\div x=5\)
\(\Leftrightarrow x=15\div5\)
\(\Leftrightarrow x=3\)
h ) \(\left(32-x\div5\right)\div13=2\)
\(\Leftrightarrow32-x\div5=2\times13\)
\(\Leftrightarrow32-x\div5=26\)
\(\Leftrightarrow x\div5=32-26\)
\(\Leftrightarrow x\div5=6\)
\(\Leftrightarrow x=5.6\)
\(\Leftrightarrow x=30\)
g ) \(\left(6-2x\right)\left(x-8\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}6-2x=0\\x-8=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=8\end{matrix}\right.\)
Vậy \(x\in\left\{3;8\right\}\)
Mình làm hết nhaa !!