\(\left[0,75-\dfrac{5}{6}\right]:\left|-\dfrac{4}{7}+\dfrac{1}{3}\right|\)
\(\left[0,75-\dfrac{5}{6}\right]:\left|-\dfrac{4}{7}+\dfrac{1}{3}\right|\)
\(\left[0,75-\dfrac{5}{6}\right]:\left|-\dfrac{4}{7}+\dfrac{1}{3}\right|\)
\(=\left[\dfrac{3}{4}-\dfrac{5}{6}\right]:\left|-\dfrac{4}{7}+\dfrac{1}{3}\right|\)
\(=\left[\dfrac{9}{12}-\dfrac{10}{12}\right]:\left|-\dfrac{12}{21}+\dfrac{7}{21}\right|\)
\(=-\dfrac{1}{12}:\dfrac{5}{21}\)
\(=-\dfrac{1}{12}\cdot\dfrac{21}{5}=-\dfrac{7}{20}\)
\(\left[0,75-\dfrac{5}{6}\right]:\left|-\dfrac{4}{7}+\dfrac{1}{3}\right|\)
\(=\left(\dfrac{3}{4}-\dfrac{5}{6}\right):\left|\dfrac{-12+7}{21}\right|\)
\(=\dfrac{9-10}{12}:\dfrac{5}{21}\)
\(=\dfrac{-1}{12}\cdot\dfrac{21}{5}=\dfrac{-21}{60}=\dfrac{-7}{20}\)
|x - 1| = |3 - 2x|
|x - 3| = |5 - 2x|
|x-1|=|3-2.x|
\(< =>\left[{}\begin{matrix}x-1=3-2.x\\x-1=-3-2.x\end{matrix}\right.< =>\left[{}\begin{matrix}2.x-x=3-1\\2.x+x=3+1\end{matrix}\right.< =>\left[{}\begin{matrix}x=2\\3.x=4\end{matrix}\right.< =>\left[{}\begin{matrix}x=2\\x=\dfrac{4}{3}\end{matrix}\right.\)
|x-3|=|5-2.x|
\(\left[{}\begin{matrix}x-3=5-2.x\\x-3=-5-2.x\end{matrix}\right.< =>\left[{}\begin{matrix}2.x-x=5-3\\2.x+x=5+3\end{matrix}\right.< =>\left[{}\begin{matrix}x=2\\3.x=8\end{matrix}\right.< =>\left[{}\begin{matrix}x=2\\x=\dfrac{8}{3}\end{matrix}\right.\)
\(\dfrac{x+2}{3}=\dfrac{-x+1}{2}\)
\(=>2\left(x+2\right)=\left(1-x\right)3\\ =>2x+4=3-3x\\ =>2x+3x=3-4\\ =>5x=-1\\ =>x=-\dfrac{1}{5}\)
(-x) mũ 6 : x mũ 3 trình bày đầy đủ giùm em
`(-x)^6 : x^3`
`= [(-x). (-x) . (-x) . (-x) . (-x) . (-x)] : (x.x.x)`
`= [ x . x.x.x.x.x] : (x.x.x)`
`= x.x.x = x^3`.
nếu a thuộc N thì a thuộc Q đúng hay sai
Vì `NN` là tập hợp con của `QQ`.
`-> A in NN -> A in QQ`.
Tìm \(x\) :
\(\left|x-3\right|\)\(+\)\(\left|5-x\right|\)\(+\)\(2\left|x-4\right|\)\(=\)\(2\)
TH1: x<3
=>3-x+5-x+8-2x=2
=>-4x+16=2
=>-4x=-14
=>x=14/4(loại)
TH2: 3<=x<4
=>x-3+5-x+8-2x=2
=>-2x+10=2
=>-2x=-8
=>x=4(loại)
Th3: 4<=x<5
=>x-3+2x-8+5-x=2
=>2x-6=2
=>x=4(nhận)
Th4: x>=5
=>x-3+x-5+2x-8=2
=>4x-16=2
=>x=18/4(loại)
Tìm x: 2x - | x + 1 | = 4
\(TH1\left|x+1\right|=x+1\\ 2x-x-1=4\\ x-1=4\\ x=5\\ TH2\left|x+1\right|=-x-1\\ 2x+x+1=4\\ 3x+1=4\\ 3x=3\\ x=1\)
Câu 15:
a: =>|x-0,4|=3,6
=>x-0,4=3,6 hoặc x-0,4=-3,6
=>x=4 hoặc x=-3,2
b: =>x-3,5=7,5 hoặc x-3,5=-7,5
=>x=11 hoặc x=-4
c: =>x-2x+5/2=7/4
=>x=5/2-7/4=3/4
tìm giá trị của y, biết rằng:
l2y - 5l = 0
\(\left|2y-5\right|=0\)
\(2y-5=0\)
\(2y=5\)
\(y=\dfrac{5}{2}\)