Tìm x biết : \(\left(x+1\right)\times\left(x^2+x+1\right)\times\left(x-1\right)\times\left(x^2-x+1\right)=7\)
Tìm x biết : \(2006\times\left|x-1\right|+\left(x-1\right)^2=2005\times\left|1-x\right|\)
2006 . | x - 1 | + ( x - 1 )2 = 2005 . | 1 - x |
\(\Rightarrow\)2006 . | x - 1 | + ( x - 1 )2 - 2005 . | 1 - x | = 0
Mà | x - 1 | = | 1 - x | = x - 1
Thay vào , ta được :
2006 . ( x - 1 ) + ( x - 1 )2 - 2005 . ( x - 1 ) = 0
( 2006 - 2005 ) . (x - 1 ) + ( x - 1 )2 = 0
( x - 1 ) + ( x - 1 )2 = 0
vì ( x - 1 )2 \(\ge\)0
\(\Rightarrow\hept{\begin{cases}x-1=0\\\left(x-1\right)^2=0\end{cases}}\)
\(\Rightarrow\hept{\begin{cases}x=1\\x=1\end{cases}\left(tm\right)}\)
Vậy x = 1
1.Rút gọn biểu thức:
\(a,\)\(x\times\left(2x^2-3\right)-x^2\left(5x+1\right)+x^2\)
\(b,\)\(3x\times\left(x-2\right)-5x\times\left(1-x\right)-8\times\left(x^2-3\right)\)
\(c,\)\(\left(2x-6\right)\times\left(x+3\right)-5\times\left(2x^2-x+7\right)\)
Tìm x \(\frac{2}{\left(x-1\right)\times\left(x-3\right)}+\frac{5}{\left(x-3\right)\times\left(x-8\right)}+\frac{12}{\left(x-8\right)\times\left(x-20\right)}-\frac{1}{x-20}=-\frac{3}{4}\)-3/4
cho: \(f\left(x\right)=a\times x^3+4\times x\times\left(x^2-1\right)+8\)
\(g\left(x\right)=x^3-4\times x\times\left(b\times x+1\right)+c-3\)
tìm a, b, c để \(f\left(x\right)=g\left(x\right)\)
Rút gọn \(B=\left(x^4-x+\frac{x-3}{x^3+1}\times\frac{\left(x^3-2x^2+2x-1\right)\left(x+1\right)}{x^9+x^7-3x^2-3}+1-\frac{2\left(x+6\right)}{x^2+1}\right)\times\frac{4x^2+6x+1}{\left(x+3\right)\left(4-x\right)}\)
Tìm x thuộc Z biết
a. \(\left(x-1\right)\times\left(2x-4\right)=0\)
b. \(\left(x^2+5\right)\times\left(x-5\right)=0\)
c. \(\left(x^2+5\right)\times\left(x^2-2\right)=0\)
d. \(\left(x^2-1\right)\times\left(x^2-9\right)< 0\)
e. \(\left|x^2-2x\right|=x\)
g. \(\left|2x+1\right|+\left|x+8\right|=4x\)
a) \(\left(x-1\right)\left(2x-4\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x-1=0\Rightarrow x=1\\2x-4=0\Rightarrow x=2\end{matrix}\right.\)
b) \(\left(x^2+5\right)\left(x-5\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x^2+5=0\Rightarrow x=-\sqrt{5}\\x-5=0\Rightarrow x=5\end{matrix}\right.\)
mà \(x\in Z\Rightarrow x=5\)
c) \(\left(x^2+5\right)\left(x^2-2\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x^2+5=0\Rightarrow x=-\sqrt{5}\\x^2-2=0\Rightarrow x=\sqrt{2}\end{matrix}\right.\)
mà \(x\in Z\Rightarrow x\in\varnothing\)
Tìm \(x\in Z\):
a. \(2\times\left(x-5\right)-3\times\left(x-4\right)=\left(-6\right)+15\times\left(-3\right)\)
b.\(\left(2x-5\right)-7=22\)
c.\(\left(2\times\left|x\right|-6\right)\times11=44\)
d.\(\left|x+3\right|+\left|x+5\right|+\left|x+9\right|=4x\)
e.\(\left|x-1\right|+\left|x-5\right|=4\)
g.\(x+\left(x+1\right)+\left(x+2\right)+.......+100=0\)
a) x=53
b) x=17
c) x=5;x=-5
d) x=17
e) x=5
g) ???
tìm x biết
\(x\times\left(4.6+\frac{3}{5}\right)+7.2-8.15\)\(42+\frac{3}{7}\times\left[3\times-1\right]=12\) \(\left[2\times x-1\right]=\left[x+2\right]\) \(\frac{x+2}{5}=\frac{2-3\times x}{3}\)a) Thiếu đề (hoặc sai)
b) x đâu?
c)\(3x-1=x+2\)
\(\Rightarrow3x-x=2+1\)
\(\Rightarrow2x=3\)
\(\Rightarrow x=\frac{3}{2}\)
c) \(\frac{x+2}{5}=\frac{2-3x}{3}\)
\(\Rightarrow3.\left(x+2\right)=5.\left(2-3x\right)\)
\(\Rightarrow3x+6=10-15x\)
\(\Rightarrow3x+15x=10-6\)
\(\Rightarrow18x=4\)
\(\Rightarrow x=\frac{4}{18}=\frac{2}{9}\)
câu 1 là \(x\times\left(4.6+\frac{3}{5}\right)=7.2-8.15\)
câu 2 là \(42+\frac{3}{7}.\left[3\times x-1=12\right]\)
a)\(x.\left(4,6+\frac{3}{5}\right)=7,2-8,15\)
\(\Rightarrow\left(\frac{23}{5}+\frac{3}{5}\right).x=-0,95\)
\(\Rightarrow\frac{26}{5}.x=\frac{-19}{20}\)
\(\Rightarrow x=\frac{-19}{20}:\frac{26}{5}\)
\(\Rightarrow x=\frac{-19}{104}\)
Mà \(4.6\)là\(4,6\)hay \(4\times6?\)nếu sai tớ làm lại
b) Ngoặc sai rồi
\(42+\frac{3}{7}.\left(3x-1\right)=12\)
\(\Rightarrow\frac{3}{7}.\left(3x-1\right)=12-42\)
\(\Rightarrow\frac{3}{7}.\left(3x-1\right)=-30\)
\(\Rightarrow3x-1=-30:\frac{3}{7}\)
\(\Rightarrow3x-1=\frac{-10}{7}\)
\(\Rightarrow3x=\frac{-10}{7}+1\)
\(\Rightarrow3x=\frac{-10+7}{7}=\frac{-3}{7}\)
\(\Rightarrow x=\frac{-3}{7}:3=\frac{-1}{7}\)
Lưu ý nhé viết dấu nhân thì viết \("."\)một thể, \("\times"\)một thể. Còn dâu phảy của số thập phân thì viết ",'' nhé
Tìm x
a, \(\left(2-x\right)\times\left(\dfrac{4}{5}-x\right)< 0\)
b, \(\left(x-\dfrac{3}{2}\right)\times\left(2\times x-1\right)>0\)
c, \(\left(x-\dfrac{4}{7}\right)\div\left(x+\dfrac{1}{2}\right)>0\)
d, \(\left(2\times x-5\right)\div\left(x+1\dfrac{3}{4}\right)< 0\)
Giúp mk với
\(a,\left(2-x\right)\left(\dfrac{4}{5}-x\right)< 0\)
=>Trong 2 số phải có 1 số âm và 1 số dương
Mà \(2-x>\dfrac{4}{5}-x\)
=>\(\dfrac{4}{5}< x< 2\)
Vậy...