4 x 5x 0,25 x1/2 x 1/2 x 2
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\(x\cdot3:x+2\cdot6:4+x:0,5+0,25+x\cdot1=35\)
=>\(3+3+2x+0,25+x=35\)
=>3x+6,25=35
=>3x=35-6,25=28,75
=>\(x=\dfrac{28.75}{3}=\dfrac{115}{12}\)
1, (0,25 - \(x\)) : - \(\dfrac{3}{5}\) = - \(\dfrac{3}{4}\)
0,25 - \(x\) = - \(\dfrac{3}{4}\) x (- \(\dfrac{3}{5}\))
0,25 - \(x\) = \(\dfrac{9}{20}\)
\(x\) = 0,25 - 0,45
\(x\) = - 0,2
2, - \(\dfrac{3}{8}\)\(x\) - 0,75 = - 1\(\dfrac{1}{2}\)
- \(\dfrac{3}{8}\)\(x\) - 0,75 = -1,5
\(\dfrac{3}{8}\)\(x\) = - 0,75 + 1,5
\(\dfrac{3}{8}\)\(x\) = 0,75
\(x\) = 0,75 : \(\dfrac{3}{8}\)
\(x\) = 2
1: \(\Leftrightarrow\dfrac{3x-1}{x+2}=4\)
=>4x+8=3x-1
=>x=-9
2: \(\Leftrightarrow\dfrac{5x-7}{2x-1}=4\)
=>8x-4=5x-7
=>3x=-3
=>x=-1
3: ĐKXD: x>=0
\(PT\Leftrightarrow\left(\sqrt{x}-2\right)\left(\sqrt{x}+3\right)=\left(\sqrt{x}+1\right)\left(\sqrt{x}-1\right)\)
=>\(x+\sqrt{x}-6=x-1\)
=>căn x=-1+6=5
=>x=25
4: ĐKXĐ: x>=0
PT =>\(\left(\sqrt{x}-3\right)\left(\sqrt{x}+1\right)=\left(\sqrt{x}-2\right)\left(\sqrt{x}+2\right)\)
=>x-2*căn x-3=x-4
=>-2căn x-3=-4
=>2căn x+3=4
=>2căn x=1
=>căn x=1/2
=>x=1/4
\(\Delta=25-4\left(4-9m\right)>0\Rightarrow36m+9>0\Rightarrow m>-\frac{1}{4}\)
\(\left\{{}\begin{matrix}x_1+x_2=-5\\x_1x_2=4-9m\end{matrix}\right.\)
\(x_1\left(x_1^2-1\right)-x_2\left(8x_2^2-1\right)=5\)
\(\Leftrightarrow x_1^3-8x_2^3-\left(x_1+x_2\right)=5\)
\(\Leftrightarrow x_1^3-8x_2^3+5=5\)
\(\Leftrightarrow x_1^3-8x_2^3=0\Rightarrow x_1^3=\left(2x_2\right)^3\Rightarrow x_1=2x_2\)
Kết hợp Viet: \(\left\{{}\begin{matrix}x_1+x_2=-5\\x_1=2x_2\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}3x_2=-5\\x_1=2x_2\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}x_2=-\frac{5}{3}\\x_1=-\frac{10}{3}\end{matrix}\right.\)
\(x_1x_2=4-9m\Rightarrow4-9m=\frac{50}{9}\Rightarrow m=-\frac{14}{81}\) (t/m)
Đề là \(x_1\left(x_1^2-1\right)-x_1\left(8x_2^2+1\right)=5\) hay \(x_2\left(x_1^2-1\right)-x_1\left(8x_2^2+1\right)=5\) hay \(x_2\left(x_1^2-1\right)+x_1\left(8x_2^2-1\right)=5\)
Nhìn đề của bạn thấy nghi ngờ quá
1: \(\Leftrightarrow2x^2-10x-3x-2x^2=0\)
=>-13x=0
=>x=0
2: \(\Leftrightarrow5x-2x^2+2x^2-2x=13\)
=>3x=13
=>x=13/3
3: \(\Leftrightarrow4x^4-6x^3-4x^3+6x^3-2x^2=0\)
=>-2x^2=0
=>x=0
4: \(\Leftrightarrow5x^2-5x-5x^2+7x-10x+14=6\)
=>-8x=6-14=-8
=>x=1
`1)2x(x-5)-(3x+2x^2)=0`
`<=>2x^2-10x-3x-2x^2=0`
`<=>-13x=0`
`<=>x=0`
___________________________________________________
`2)x(5-2x)+2x(x-1)=13`
`<=>5x-2x^2+2x^2-2x=13`
`<=>3x=13<=>x=13/3`
___________________________________________________
`3)2x^3(2x-3)-x^2(4x^2-6x+2)=0`
`<=>4x^4-6x^3-4x^4+6x^3-2x^2=0`
`<=>x=0`
___________________________________________________
`4)5x(x-1)-(x+2)(5x-7)=0`
`<=>5x^2-5x-5x^2+7x-10x+14=0`
`<=>-8x=-14`
`<=>x=7/4`
___________________________________________________
`5)6x^2-(2x-3)(3x+2)=1`
`<=>6x^2-6x^2-4x+9x+6=1`
`<=>5x=-5<=>x=-1`
___________________________________________________
`6)2x(1-x)+5=9-2x^2`
`<=>2x-2x^2+5=9-2x^2`
`<=>2x=4<=>x=2`
a: =>3,6-x+0,5=3,5-0,75+x
=>4,1-x=x+2,75
=>-2x=-1,35
=>x=0,675
b: =>5x^2-5x+x-1=0
=>(x-1)(5x+1)=0
=>x=1 hoặc x=-1/5
c: \(\Leftrightarrow\left(\dfrac{2-x}{2008}+1\right)=\left(\dfrac{1-x}{2009}+1\right)+\left(1-\dfrac{x}{2010}\right)\)
=>\(2010-x=0\)
=>x=2010
4 x 5 x 0,25 x 1/2 x 1/2 x 2
=5 x 1 x 1/2 x 1
=5 x 1/2
=5/2
=20 x (0,25 x 2) x (1/2 x 1/2)
=20 x 0,5 x 1/4
=20 x 1/8
=5/2