Đáp án:
Giải thích các bước giải:
\[\begin{array}{l}a)\left( {x - 289} \right) \times 47{\rm{ }} = {\rm{ }}0\\ \Leftrightarrow x - 289 = 0\\ \Leftrightarrow x = 289\\b)54\left( {84 - x} \right){\rm{ }} = {\rm{ }}54x\\ \Leftrightarrow x - 84 = x\\ \Leftrightarrow 0x = 84\\ \Rightarrow Khong\,co\,gia\,tri\,nao\,cua\,x\,thoa\,man\\c)7{\rm{ }} \times {\rm{ }}x{\rm{ }} - 10{\rm{ }} = 704\\ \Leftrightarrow 7 \times x = 704 + 10\\ \Rightarrow 7 \times x = 714\\ \Leftrightarrow \,\,\,\,\,\,\,\,x = 714:7\\ \Leftrightarrow \,\,\,\,\,\,\,\,x = 102\\B3:\\a)2x{\rm{ }} + {\rm{ }}3x = 1505\\\,\, \Leftrightarrow \,\,\,\,\,\,\,5x\,\,\,\,\,\, = 1505\\\, \Leftrightarrow \,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\, = 1505:5\\\, \Leftrightarrow \,\,\,\,\,\,\,x\,\,\,\,\,\,\,\,\, = 301\\b)5x{\rm{ }} - {\rm{ }}x{\rm{ }} = 4088\\ \Leftrightarrow \,\,\,\,\,\,4x\,\,\,\,\,\,\, = 4088\\ \Leftrightarrow \,\,\,\,\,\,x\,\,\,\,\,\,\, = 4088:4\\ \Leftrightarrow \,\,\,\,\,\,x\,\,\,\,\,\,\, = 1022\end{array}\]
