Tim x biet 2.3x+2+3x+1+3x-1=26.92
tim x biet x^3-3x^2+3x-1=0
x^3 - 3x^2 + 3x - 1 = 0
( x- 1)^3 = 0
=> x -1 = 0
=> x = 1
Tim x biet:
(3/4x + 5) - (2/3x - 4) - (1/6x + 1) = (1/3x + 4) - (1/3x - 3)
3/4x + 5-(2/3x-4)-(1/6+1)=(1/3x+4)-(1/3x-3)
=3/4x+5-2/3x-4-1/6x+1=1/3x+4-1/3x-3
=-1/12=7
x=84
Đ/S...
tim x biet
|x+1|+|3x+2|=3x
|x-2|+4|x+1|=x-3
a) (2+√3)2x=2-√3
b) 2x2-3x+2=4
c) 2.3x+1-6.3x-1-3x=9
d) log3(3x+8)=2+x
Tim x biet: (3/4x+5)-(2/3x-4)-(1/6x+1)=(1/3+4)-(1/3x-3)
\(\left(\dfrac{3x}{4}+5\right)-\left(\dfrac{2x}{3}-4\right)-\left(\dfrac{x}{6}+1\right)=\left(\dfrac{1}{3}+4\right)-\left(\dfrac{1}{3}x-3\right)\)
\(\Leftrightarrow\dfrac{3x}{4}-\dfrac{2x}{3}-\dfrac{x}{6}+5+4-1=\dfrac{13}{3}-\dfrac{1}{3}x+9\)
\(\Leftrightarrow\dfrac{9x-8x-2x}{12}+8=\dfrac{13-x}{3}+\dfrac{27}{3}\)
\(\Leftrightarrow\dfrac{-x}{12}+\dfrac{96}{12}=\dfrac{40-x}{3}\Leftrightarrow\dfrac{96-x}{12}=\dfrac{160-4x}{12}\)
\(\Rightarrow96-160=-4x+x\Leftrightarrow-64=-3x\Leftrightarrow x=\dfrac{64}{3}\)
A=x+6x^2+7x^2-6x+1
A=(x^2)^2+2x^2.3x+9x^2-1x^2-6x+7
A=(x^2+3x)^2-2.(x^2+3x).1+1
A=(x^2+3x)^2>=0 với mọi x khi x^2=3x-1=0
tim x biet |2-3x|=x-1
|2-3x|=x-1
2-3x=x-1 hoặc 2-3x=x-1
TH1:2-3x=x-1
3x-x=2-(-1)
2x=2+1
2x=3
x=3/2
TH2:2-3x=-(x-1)
2-3x=-x+1
3x+x=2-1
4x=1
x=1/4
Ta có : |2 - 3x| = x - 1
\(\Leftrightarrow\orbr{\begin{cases}2-3x=x-1\\2-3x=-x+1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}-3x-x=-1-2\\-3x+x=1-2\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}-4x=-3\\-2x=-1\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=\frac{3}{4}\\x=\frac{1}{2}\end{cases}}\)
tim x biet /x^2+/3x-1//=x^2+7
|x2+|3x-1||=x2+7
Vì |x2+|3x-1|| \(\ge\) 0;
x2+7 \(\ge\) 0
nên VT=VP
<=>x2+|3x-1|=x2+7
<=>|3x-1|=x2+7-x2=7
<=>\(\int^{3x-1=7\Rightarrow3x=8\Rightarrow x=\frac{8}{3}}_{3x-1=-7\Rightarrow3x=-6\Rightarrow x=-2}\)
Vậy x \(\in\) (-2;8/3}
tim x biet /3x-2/-x>1
tim x biet x^2+3x+1=0