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\(\frac{8}{3}:x=\frac{16}{9}:\frac{8}{3}\)
\(\frac{8}{3}:x=\frac{16}{9}.\frac{3}{8}\)
\(\frac{8}{3}:x=\frac{2}{3}\)
\(x=\frac{8}{3}:\frac{2}{3}\)
\(x=\frac{8}{3}.\frac{3}{2}\)
\(x=4\)
Vậy x = 4
Ta có: \(x+\frac{1}{9}=\frac{8}{x}-1\)
\(\Leftrightarrow x-\frac{8}{x}=-1-\frac{1}{9}\)
\(\Leftrightarrow\frac{x^2-8}{x}=-\frac{10}{9}\)
\(\Leftrightarrow9.\left(x^2-8\right)=-10x\)
\(\Leftrightarrow9x^2+10x-72=0\)
\(\Leftrightarrow\left(9x^2+10x+\frac{25}{9}\right)-\frac{673}{9}=0\)
\(\Leftrightarrow\left(3x+\frac{5}{3}\right)^2=\frac{673}{9}\)
\(\Leftrightarrow3x+\frac{5}{3}=\pm\frac{\sqrt{673}}{3}\)
+ \(3x+\frac{5}{3}=\frac{\sqrt{673}}{3}\)\(\Leftrightarrow\)\(3x=\frac{\sqrt{673}-5}{3}\)
\(\Leftrightarrow\)\(x=\frac{\sqrt{673}-5}{9}\)
+ \(3x+\frac{5}{3}=-\frac{\sqrt{673}}{3}\)\(\Leftrightarrow\)\(3x=\frac{-\sqrt{673}-5}{3}\)
\(\Leftrightarrow\)\(x=\frac{-\sqrt{673}-5}{9}\)
Vậy \(x\in\left\{\frac{\sqrt{673}-5}{9};\frac{-\sqrt{673}-5}{9}\right\}\)
Từ đề bài=>(x+1)/10+(x+2)/9+(x+3)/8-(-3)=0
<=>......................................(như trên)+3=0
<=>(x+1)/10+1+(x+2)/9+1+(x+3)/8+1=0( vì 1+1+1=3)
<=>(x+1+10)/10+(x+2+9)/9+(x+3+8)/8=0
<=>(x+11)/10+(x+11)/9+(x+11)/8=0
<=>(x+11).(1/10+1/9+1/8)=0
Mà 1/10<1/9<1/8
=>1/10+1/9+1/8 khác 0
<=>x+11=0<=>x=-11
Vậy x=-11
Đề:
Giài:
\(\frac{31}{9}\left|x\right|=\frac{8}{3}+\frac{5}{2}\)
\(\frac{31}{9}\left|x\right|=\frac{31}{6}\)
\(\left|x\right|=\frac{31}{6}:\frac{31}{9}\)
\(\left|x\right|=\frac{3}{2}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{3}{2}\\x=\frac{-3}{2}\end{cases}}\)
Vậy x = \(\frac{3}{2}\)hoặc x = \(\frac{-3}{2}\)
\(\frac{31}{9}\left|x\right|-\frac{5}{2}=\frac{8}{3}\)
\(\frac{31}{9}\left|x\right|=\frac{8}{3}+\frac{5}{2}\)
\(\frac{31}{9}\left|x\right|=\frac{8\cdot2}{6}+\frac{5\cdot3}{6}\)
\(\frac{31}{9}\left|x\right|=\frac{16}{6}+\frac{15}{6}\)
\(\frac{31}{9}\left|x\right|=\frac{31}{6}\)
\(\left|x\right|=\frac{31}{6}:\frac{31}{9}\)
\(\left|x\right|=\frac{31}{6}\cdot\frac{9}{31}\)
\(\left|x\right|=\frac{1}{2}\cdot\frac{3}{1}\)
\(\Leftrightarrow\hept{\begin{cases}x=\frac{3}{2}\\x=-\frac{3}{2}\end{cases}}\)
Vậy \(x\in\left\{\frac{3}{2};-\frac{3}{2}\right\}\)
Nếu x < 2
=> |x - 2| = -(x - 2) = -x + 2
=> |x - 3| = -(x - 3) = -x + 3
=> |2x - 8| = -(2x - 8) = -2x + 8
Khi đó |x - 2| + |x - 3| + |2x - 8| = 9 (1)
<=> -x + 2 -x + 3 - 2x + 8 = 9
=> -4x + 13 = 9
=> -4x = -4
=> x = 1 (tm)
Nếu 2 \(\le x< 3\)
=> |x - 2| = x - 2
=> |x - 3| = -(x - 3) = -x + 3
=> |2x - 8| = -(2x - 8) = -2x + 8
Khi đó (1) <=> x - 2 - x + 3 - 2x + 8 = 9
=> -2x + 9 = 9
=> -2x = 0
=> x = 0 (loại)
Nếu \(3\le x\le4\)
=> |x - 2| = x - 2
=> |x - 3| = x - 3
=> |2x - 8| = -(2x - 8) = -2x + 8
Khi đó (1) <=> x - 2 + x - 3 - 2x + 8 = 9
=> 0x + 3 = 9
=> 0x = 6 (loại)
Nếu x > 4
=> |x - 2| = x - 2
=> |x - 3| = x - 3
=> |2x - 8| = 2x - 8
Khi đó (1) <=> x - 2 + x - 3 + 2x - 8 = 9
=> 4x - 13 = 9
=> 4x = 22
=> x = 5,5 (tm)
Vậy \(x\in\left\{1;5,5\right\}\)