tìm x biết
( 3x - 4 )3 = 7 + 12019
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
`(3x-4)^3=7+1^2019`
`(3x-4)^3=7+1`
`(3x-4)^3=8`
`(3x-4)^3=2^3`
`=>3x-4=2`
`3x=6`
`x=2`
\(\left(3x-4\right)^3=7+1^{2019}\)
\(\left(3x-4\right)^3=7+1=8=2^3\)
\(=>3x-4=2\)
\(3x=2+4\)
\(3x=6\)
\(x=6:3\)
\(x=2\)
\(a,x+\frac{3}{4}=\frac{1}{4}\)
\(\Rightarrow x=\frac{1}{4}-\frac{3}{4}=-\frac{1}{2}\)
\(b,\frac{2}{3}x-\frac{3}{7}=\frac{1}{7}\)
\(\Rightarrow\frac{2}{3}x=\frac{1}{7}+\frac{3}{7}\)
\(\Rightarrow\frac{2}{3}x=\frac{4}{7}\)
\(\Rightarrow x=\frac{4}{7}:\frac{2}{3}=\frac{4}{7}\cdot\frac{3}{2}=\frac{6}{7}\)
\(c,1\frac{2}{3}x-50\%x=-1\frac{1}{6}\)
\(\Rightarrow\frac{5}{3}x-\frac{50}{100}x=-\frac{7}{6}\)
\(\Rightarrow\left[\frac{5}{3}-\frac{50}{100}\right]x=-\frac{7}{6}\)
\(\Rightarrow\left[\frac{5}{3}-\frac{1}{2}\right]x=-\frac{7}{6}\)
\(\Rightarrow\frac{7}{6}x=-\frac{7}{6}\Leftrightarrow x=-\frac{7}{6}:\frac{7}{6}=-\frac{7}{6}\cdot\frac{6}{7}=-1\)
a,x+\(\frac{3}{4}\)=\(\frac{1}{4}\)
=>x =\(\frac{1}{4}\)-\(\frac{3}{4}\)
=> x =\(\frac{-1}{2}\)
Vậy x=\(\frac{-1}{2}\)
b,\(\frac{2}{3}\)x-\(\frac{3}{7}\)=\(\frac{1}{7}\)
=>\(\frac{2}{3}\)x =\(\frac{1}{7}\)+\(\frac{3}{7}\)
=>\(\frac{2}{3}\)x =\(\frac{4}{7}\)
=> x =\(\frac{4}{7}\) :\(\frac{2}{3}\)
=> x =\(\frac{4}{7}\).\(\frac{3}{2}\)
=> x =\(\frac{6}{7}\)
Vậy x=\(\frac{6}{7}\)
c,\(\frac{12}{3}\)x-50%x =\(\frac{-11}{6}\)
=>\(\frac{12}{3}\)x-\(\frac{1}{2}\)x=\(\frac{-11}{6}\)
=>x(\(\frac{12}{3}\)-\(\frac{1}{2}\))=\(\frac{-11}{6}\)
=>x(\(\frac{24}{6}\)-\(\frac{3}{6}\))=\(\frac{-11}{6}\)
=>x\(\frac{21}{6}\) =\(\frac{-11}{6}\)
=>x =\(\frac{-11}{6}\):\(\frac{21}{6}\)
=>x =\(\frac{-11}{6}\).\(\frac{6}{21}\)
=>x =\(\frac{-11}{21}\)
Vậy x=\(\frac{-11}{21}\)
5) // 3x + 1 / - 5 / = 2
=> / 3x + 1 / -5 = 2 hoặc -2
TH1: / 3x + 1 / - 5 = 2 => / 3x + 1 / = 2 + 5 = 7 => 3x + 1 = 7 hoặc -7
*1: 3x + 1 = -7 => 3x = -7 - 1 = -8 => x = -8/3
*2: 3x + 1 = 7 => 3x = 7 - 1 = 6 => x = 6 : 3 = 2
TH2: / 3x + 1 / - 5 = -2 => / 3x + 1/ = -2 + 5 = 3 => 3x + 1 = 3 hoặc -3
*1: 3x + 1 = 3 => 3x = 3 - 1 = 2 => x = 2/3
*2: 3x + 1 = -3 => 3x = -3 - 1 = -4 => x = -4/3
Vậy x thuộc { -8/3 ; 2 ; 2/3 ; -4/3 }
7) 3/2 + 4/5 /x - 3/4 / = 7/4
=> 4/5 / x - 3/4 / = 7/4 - 4/5
=> 4/5 / x - 3/4 / = 19/20
=> / x - 3/4 / = 19/20 : 4/5
=> / x - 3/4 / = 19/16
=> / x - 3/4 / = 19/16 hoặc -19/16
\(\left(3x-4\right)^3=7+1^{2019}\)
\(\Leftrightarrow\left(3x-4\right)^3=7+1\)
\(\Leftrightarrow\left(3x-4\right)^3=8\)
\(\Leftrightarrow\left(3x-4\right)^3=2^3\)
\(\Leftrightarrow3x-4=2\)
\(\Leftrightarrow3x=6\)
\(\Leftrightarrow x=2\)