Bài 1 : Tìm x a. x^2 × 23 – x^2 × 3 = 80 b. | x – 3 | – ( -5 ) = 15 03/11/2021 Bởi Aaliyah Bài 1 : Tìm x a. x^2 × 23 – x^2 × 3 = 80 b. | x – 3 | – ( -5 ) = 15
`a/` `x^{2}.23-x^{2}.3=80` `x^{2}(23-3)=80` `x^{2}.20=80` `x^2=80:20` `x^2=4` `x^2=2^2` `=>`\(\left[ \begin{array}{l}x=2\\x=-2\end{array} \right.\) `\text{Vậy x có thể bằng (-2) hoặc 2}` `b/` `|x -3|-(-5) = 15` `|x -3|+5=15` `|x -3|=15-5` `|x -3|=10` `=>`\(\left[ \begin{array}{l}x-3=-10\\x-3=10\end{array} \right.\) `=>`\(\left[ \begin{array}{l}x-3=-7\\x-3=13\end{array} \right.\) `\text{Vậy x có thể bằng (-7) hoặc 13}` Bình luận
`a)x^2 . 23 -x^2 .3=80` `→x^2(23-3)=80` `→x^2 . 20=80` `→x^2=80:20` `→x^2=4` `→x^2=2^2` `→` \(\left[ \begin{array}{l}x=2\\x=-2\end{array} \right.\) Vậy `x∈{2;-2}` `b)|x-3|-(-5)=15` `→|x-3|+5=15` `→|x-3|=15-5` `→|x-3|=10` `→` \(\left[ \begin{array}{l}x-3=10\\x-3=-10\end{array} \right.\) `→` \(\left[ \begin{array}{l}x=13\\x=-7\end{array} \right.\) Vậy `x∈{13;-7}` Bình luận
`a/`
`x^{2}.23-x^{2}.3=80`
`x^{2}(23-3)=80`
`x^{2}.20=80`
`x^2=80:20`
`x^2=4`
`x^2=2^2`
`=>`\(\left[ \begin{array}{l}x=2\\x=-2\end{array} \right.\)
`\text{Vậy x có thể bằng (-2) hoặc 2}`
`b/`
`|x -3|-(-5) = 15`
`|x -3|+5=15`
`|x -3|=15-5`
`|x -3|=10`
`=>`\(\left[ \begin{array}{l}x-3=-10\\x-3=10\end{array} \right.\)
`=>`\(\left[ \begin{array}{l}x-3=-7\\x-3=13\end{array} \right.\)
`\text{Vậy x có thể bằng (-7) hoặc 13}`
`a)x^2 . 23 -x^2 .3=80`
`→x^2(23-3)=80`
`→x^2 . 20=80`
`→x^2=80:20`
`→x^2=4`
`→x^2=2^2`
`→` \(\left[ \begin{array}{l}x=2\\x=-2\end{array} \right.\)
Vậy `x∈{2;-2}`
`b)|x-3|-(-5)=15`
`→|x-3|+5=15`
`→|x-3|=15-5`
`→|x-3|=10`
`→` \(\left[ \begin{array}{l}x-3=10\\x-3=-10\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=13\\x=-7\end{array} \right.\)
Vậy `x∈{13;-7}`