Đáp án:
`↓↓`
Giải thích các bước giải:
`a) (2x-1)^2=169`
`=> (2x-1)^2=(+-13)^2`
`=>` \(\left[ \begin{array}{l}2x-1=13\\2x-1=-13\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=7\\x=-6\end{array} \right.\)
`b) 3^x+3^(x+2)=270`
`=> 3^x. 1+3^x. 3^2=270`
`=> 3^x. (1+3^2)=270`
`=> 3^x. 10=270`
`=> 3^x=27`
`=> 3^x=3^3`
`=> x=3`
`c)` Ta có: `125 vdots x, 100 vdots x`
`=> x in ƯC(125; 100)`
`125=5^3`
`100=2^2. 5^2`
`=> ƯCLN(125,100)=5^2=25`
`=> x in Ư(25)={1; 5; 25}`
Mà `x>10`
`=> x=25`
