Đáp án:
`2x -60:15=2=> x=3`
`(2x -15)^5 =(2x-15)^3=> x\in {(15)/2;7;8}``
Giải thích các bước giải:
`2x -60:15=2`
`<=> 2x -4=2`
`<=> 2x =2+4`
`<=> 2x =6`
`<=> x=6:2`
`<=> x=3`
Vậy `x=3`
`(2x -15)^5 =(2x-15)^3`
`<=> (2x-15)^5 -(2x-15)^3`
`<=> (2x-15)^3 [(2x-15)^2 -1]=0`
`<=>`\(\left[ \begin{array}{l}(2x-15)^3 =0\\(2x-15)^2-1=0\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}2x -15=0\\2x-15=±1\end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}2x =15\\2x-15=1 \\ 2x -15 =-1 \end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}2x =15\\2x=16 \\ 2x =14 \end{array} \right.\)
`<=>`\(\left[ \begin{array}{l}x=\dfrac{15}{2}\\x=8\\ x=7\end{array} \right.\)
Vậy `x \in {(15)/2;7;8}`
