Tìm số thực x biết : (3.x-5/12)^2-121/64=0 05/12/2021 Bởi Hailey Tìm số thực x biết : (3.x-5/12)^2-121/64=0
`(3x-5/12)^2-121/64=0` `↔(3x-5/12)^2=121/64` `↔(3x-5/12)^2=(11/8)^2` `↔3x-5/12=11/8` hoặc `3x-5/12=(-11)/8` `↔3x=43/24` hoặc `3x=(-23)/24` `↔x=43/72` hoặc `x=(-23)/72` Vậy `x∈{43/72;(-23)/72}` Bình luận
` (3x-5/12)^2-121/64=0` `\to (3x-5/12)^2-(11/8)^2=0` ` \to(3x-5/12)^2=(11/8)^2` \(\to\left[ \begin{array}{l}3x-\cfrac5{12}=\cfrac{11}8\\3x-\cfrac5{12}=-\cfrac{11}8\end{array} \right.\) \(\to\left[ \begin{array}{l}3x=\cfrac{11}8+\cfrac5{12}\\3x=\cfrac5{12}-\cfrac{11}8\end{array} \right.\) \(\to\left[ \begin{array}{l}3x=\cfrac{43}{24}\\3x=\cfrac{-23}{24}\end{array} \right.\) \(\to\left[ \begin{array}{l}x=\cfrac{43}{72}\\x=\cfrac{-23}{72}\end{array} \right.\) Bình luận
`(3x-5/12)^2-121/64=0`
`↔(3x-5/12)^2=121/64`
`↔(3x-5/12)^2=(11/8)^2`
`↔3x-5/12=11/8` hoặc `3x-5/12=(-11)/8`
`↔3x=43/24` hoặc `3x=(-23)/24`
`↔x=43/72` hoặc `x=(-23)/72`
Vậy `x∈{43/72;(-23)/72}`
` (3x-5/12)^2-121/64=0`
`\to (3x-5/12)^2-(11/8)^2=0`
` \to(3x-5/12)^2=(11/8)^2`
\(\to\left[ \begin{array}{l}3x-\cfrac5{12}=\cfrac{11}8\\3x-\cfrac5{12}=-\cfrac{11}8\end{array} \right.\)
\(\to\left[ \begin{array}{l}3x=\cfrac{11}8+\cfrac5{12}\\3x=\cfrac5{12}-\cfrac{11}8\end{array} \right.\)
\(\to\left[ \begin{array}{l}3x=\cfrac{43}{24}\\3x=\cfrac{-23}{24}\end{array} \right.\)
\(\to\left[ \begin{array}{l}x=\cfrac{43}{72}\\x=\cfrac{-23}{72}\end{array} \right.\)