Giải thích các bước giải: Ta có: \(\begin{array}{l}a,\\6.x – 5 = 613\\ \Leftrightarrow 6.x = 613 + 5\\ \Leftrightarrow 6.x = 618\\ \Leftrightarrow x = 618:6\\ \Leftrightarrow x = 103\\b,\\\left( {x – 47} \right) – 115 = 0\\ \Leftrightarrow x – 47 = 115\\ \Leftrightarrow x = 115 + 47\\ \Leftrightarrow x = 162\\c,\\315 + \left( {146 – x} \right) = 401\\ \Leftrightarrow 146 – x = 401 – 315\\ \Leftrightarrow 146 – x = 86\\ \Leftrightarrow x = 146 – 86\\ \Leftrightarrow x = 60\\d,\\575 – \left( {6x + 70} \right) = 445\\ \Leftrightarrow 6x + 70 = 575 – 445\\ \Leftrightarrow 6x + 70 = 130\\ \Leftrightarrow 6x = 130 – 70\\ \Leftrightarrow 6x = 60\\ \Leftrightarrow x = 10\\e,\\x – 105:21 = 15\\ \Leftrightarrow x – 5 = 15\\ \Leftrightarrow x = 20\\f,\\\left( {x – 105} \right):21 = 15\\ \Leftrightarrow x – 105 = 15.21\\ \Leftrightarrow x – 105 = 315\\ \Leftrightarrow x = 420\\g,\\2448:\left[ {119 – \left( {x – 6} \right)} \right] = 24\\ \Leftrightarrow 119 – \left( {x – 6} \right) = 2448:24\\ \Leftrightarrow 119 – x + 6 = 102\\ \Leftrightarrow 125 – x = 102\\ \Leftrightarrow x = 125 – 102\\ \Leftrightarrow x = 23\\h,\\x:2 = x:3\\ \Leftrightarrow x = 2x:3\\ \Leftrightarrow 3x = 2x\\ \Leftrightarrow x = 0\\i,\\\left( {4x + 5} \right):3 – 121:11 = 4\\ \Leftrightarrow \left( {4x + 5} \right):3 – 11 = 4\\ \Leftrightarrow \left( {4x + 5} \right):3 = 15\\ \Leftrightarrow 4x + 5 = 45\\ \Leftrightarrow 4x = 40\\ \Leftrightarrow x = 10\\k,\\5x – x = 84\\ \Leftrightarrow 4x = 84\\ \Leftrightarrow x = 21\\i,\\0.\left( {7 – x} \right) = 0,\,\,\,\forall x\end{array}\) Reply
Giải thích các bước giải:
Ta có:
\(\begin{array}{l}
a,\\
6.x – 5 = 613\\
\Leftrightarrow 6.x = 613 + 5\\
\Leftrightarrow 6.x = 618\\
\Leftrightarrow x = 618:6\\
\Leftrightarrow x = 103\\
b,\\
\left( {x – 47} \right) – 115 = 0\\
\Leftrightarrow x – 47 = 115\\
\Leftrightarrow x = 115 + 47\\
\Leftrightarrow x = 162\\
c,\\
315 + \left( {146 – x} \right) = 401\\
\Leftrightarrow 146 – x = 401 – 315\\
\Leftrightarrow 146 – x = 86\\
\Leftrightarrow x = 146 – 86\\
\Leftrightarrow x = 60\\
d,\\
575 – \left( {6x + 70} \right) = 445\\
\Leftrightarrow 6x + 70 = 575 – 445\\
\Leftrightarrow 6x + 70 = 130\\
\Leftrightarrow 6x = 130 – 70\\
\Leftrightarrow 6x = 60\\
\Leftrightarrow x = 10\\
e,\\
x – 105:21 = 15\\
\Leftrightarrow x – 5 = 15\\
\Leftrightarrow x = 20\\
f,\\
\left( {x – 105} \right):21 = 15\\
\Leftrightarrow x – 105 = 15.21\\
\Leftrightarrow x – 105 = 315\\
\Leftrightarrow x = 420\\
g,\\
2448:\left[ {119 – \left( {x – 6} \right)} \right] = 24\\
\Leftrightarrow 119 – \left( {x – 6} \right) = 2448:24\\
\Leftrightarrow 119 – x + 6 = 102\\
\Leftrightarrow 125 – x = 102\\
\Leftrightarrow x = 125 – 102\\
\Leftrightarrow x = 23\\
h,\\
x:2 = x:3\\
\Leftrightarrow x = 2x:3\\
\Leftrightarrow 3x = 2x\\
\Leftrightarrow x = 0\\
i,\\
\left( {4x + 5} \right):3 – 121:11 = 4\\
\Leftrightarrow \left( {4x + 5} \right):3 – 11 = 4\\
\Leftrightarrow \left( {4x + 5} \right):3 = 15\\
\Leftrightarrow 4x + 5 = 45\\
\Leftrightarrow 4x = 40\\
\Leftrightarrow x = 10\\
k,\\
5x – x = 84\\
\Leftrightarrow 4x = 84\\
\Leftrightarrow x = 21\\
i,\\
0.\left( {7 – x} \right) = 0,\,\,\,\forall x
\end{array}\)