Tìm x a) x – 7/ 36 = -4/ 7-x b) 0,2/ |2x-1|- 20/11.13 – 20/13.15 – 20/ 15.17-….-20/53.55=3/11 29/07/2021 Bởi Kinsley Tìm x a) x – 7/ 36 = -4/ 7-x b) 0,2/ |2x-1|- 20/11.13 – 20/13.15 – 20/ 15.17-….-20/53.55=3/11
Đáp án: `a)` `(x-7)/36 = -4/(7-x)` `to (x-7)/36 = 4/(x-7)` `to (x-7)^2=144` `to` \(\left[ \begin{array}{l}x-7=12\\x-7=-12\end{array} \right.\) `to` \(\left[ \begin{array}{l}x=19\\x=-5\end{array} \right.\) Vậy `x in {-5;19}` `b)` `(0,2)/ |2x-1|- 20/11.13 – 20/13.15 – 20/ 15.17-….-20/53.55=3/11` `to (0,2)/|2x-1| – 10.(2/11.13+2/13.15+2/15.17+…+2/53.55)=3/11` `to (0,2)/|2x-1| – 10.(1/11-1/13+1/13-1/15+1/15-1/17+…+1/53-1/55)=3/11` `to (0,2)/|2x-1| – 10.(1/11-1/55)=3/11` `to (0,2)/|2x-1| – 10. 4/55=3/11` `to (0,2)/|2x-1| – 8/11 = 3/11` `to (0,2)/|2x-1| = 1` `to |2x-1|=0,2` `to |2x-1|=1/5` `to` \(\left[ \begin{array}{l}2x-1=\dfrac{1}{5}\\2x-1=-\dfrac{1}{5}\end{array} \right.\) `to` \(\left[ \begin{array}{l}2x=\dfrac{6}{5}\\2x=\dfrac{4}{5}\end{array} \right.\) `to` \(\left[ \begin{array}{l}x=\dfrac{3}{5}\\x=\dfrac{2}{5}\end{array} \right.\) Vậy `x in {3/5;2/5}` Bình luận
Đáp án: Giải thích các bước giải: `a)“x-7/36=(-4)/7-x` `x+x=7/36+(-4)/7` `2x=(-95)/252` `x=(-95)/490` `b)“(0,2)/(|2x-1|)-20/11.13-20/13.15-20/15.17-…-20/53.55=3/11` `(0,2)/(|2x-1|)-(20/11.13+20/13.15+20/15.17+…+20/53.55)=3/11` `(0,2)/(|2x-1|)-10(2/11.13+2/13.15+2/15.17+…+2/53.55)=3/11` `(0,2)/(|2x-1|)-10(1/11-1/13+1/13-1/15+1/15-1/17+…+1/53-1/55)=3/11` `(0,2)/(|2x-1|)-10(1/11-1/55)=3/11` `(0,2)/(|2x-1|)-10*4/55=3/11` `(0,2)/(|2x-1|)-8/11=3/11` `(0,2)/(|2x-1|)=1` `|2x-1|=0,2.1` `|2x-1|=1/5` \(\left\{ \begin{array}{l}2x-1=\dfrac{1}{5}\\2x-1=\dfrac{-1}{5}\end{array} \right.\)`=>`\(\left\{ \begin{array}{l}x=\dfrac{3}{5}\\x=\dfrac{2}{5}\end{array} \right.\) Bình luận
Đáp án:
`a)`
`(x-7)/36 = -4/(7-x)`
`to (x-7)/36 = 4/(x-7)`
`to (x-7)^2=144`
`to` \(\left[ \begin{array}{l}x-7=12\\x-7=-12\end{array} \right.\) `to` \(\left[ \begin{array}{l}x=19\\x=-5\end{array} \right.\)
Vậy `x in {-5;19}`
`b)`
`(0,2)/ |2x-1|- 20/11.13 – 20/13.15 – 20/ 15.17-….-20/53.55=3/11`
`to (0,2)/|2x-1| – 10.(2/11.13+2/13.15+2/15.17+…+2/53.55)=3/11`
`to (0,2)/|2x-1| – 10.(1/11-1/13+1/13-1/15+1/15-1/17+…+1/53-1/55)=3/11`
`to (0,2)/|2x-1| – 10.(1/11-1/55)=3/11`
`to (0,2)/|2x-1| – 10. 4/55=3/11`
`to (0,2)/|2x-1| – 8/11 = 3/11`
`to (0,2)/|2x-1| = 1`
`to |2x-1|=0,2`
`to |2x-1|=1/5`
`to` \(\left[ \begin{array}{l}2x-1=\dfrac{1}{5}\\2x-1=-\dfrac{1}{5}\end{array} \right.\) `to` \(\left[ \begin{array}{l}2x=\dfrac{6}{5}\\2x=\dfrac{4}{5}\end{array} \right.\) `to` \(\left[ \begin{array}{l}x=\dfrac{3}{5}\\x=\dfrac{2}{5}\end{array} \right.\)
Vậy `x in {3/5;2/5}`
Đáp án:
Giải thích các bước giải:
`a)“x-7/36=(-4)/7-x`
`x+x=7/36+(-4)/7`
`2x=(-95)/252`
`x=(-95)/490`
`b)“(0,2)/(|2x-1|)-20/11.13-20/13.15-20/15.17-…-20/53.55=3/11`
`(0,2)/(|2x-1|)-(20/11.13+20/13.15+20/15.17+…+20/53.55)=3/11`
`(0,2)/(|2x-1|)-10(2/11.13+2/13.15+2/15.17+…+2/53.55)=3/11`
`(0,2)/(|2x-1|)-10(1/11-1/13+1/13-1/15+1/15-1/17+…+1/53-1/55)=3/11`
`(0,2)/(|2x-1|)-10(1/11-1/55)=3/11`
`(0,2)/(|2x-1|)-10*4/55=3/11`
`(0,2)/(|2x-1|)-8/11=3/11`
`(0,2)/(|2x-1|)=1`
`|2x-1|=0,2.1`
`|2x-1|=1/5`
\(\left\{ \begin{array}{l}2x-1=\dfrac{1}{5}\\2x-1=\dfrac{-1}{5}\end{array} \right.\)`=>`\(\left\{ \begin{array}{l}x=\dfrac{3}{5}\\x=\dfrac{2}{5}\end{array} \right.\)