Tìm x
a, 48- 2 ( 2x - 1 )3 = 102
b, ( 1/3 )x = 1/81
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ND
1
23 tháng 7 2015
1+2+3+....+999
=\(\frac{999.\left(999+1\right)}{2}\)
=999000/2
=499500
x^2.x^4.x^6.x^8....x^48...x^50
=x(2+4+6+8+...+48+50)
=x650
tìm X
5^x=125
5^x=5^3
x=3
3^2x=81
3^2x=3^4
2x=4
x=4:2
x=2
**** nhé
24 tháng 12 2023
a: \(\left(2x-3\right)^2=\left|3-2x\right|\)
=>\(\left\{{}\begin{matrix}\left|2x-3\right|>=0\\\left(2x-3\right)^2=\left(2x-3\right)\end{matrix}\right.\Leftrightarrow\left(2x-3\right)^2-\left(2x-3\right)=0\)
=>\(\left(2x-3\right)\left(2x-3-1\right)=0\)
=>\(\left(2x-3\right)\left(2x-4\right)=0\)
=>\(\left[{}\begin{matrix}2x-3=0\\2x-4=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=2\end{matrix}\right.\)
b: \(\left(x-1\right)^2+\left(2x-1\right)^2=0\)
=>\(x^2-2x+1+4x^2-4x+1=0\)
=>\(5x^2-6x+2=0\)
\(\Delta=\left(-6\right)^2-4\cdot5\cdot2=36-20\cdot2=-4< 0\)
=>Phương trình vô nghiệm
c: ĐKXĐ: x>=0
\(x-2\sqrt{x}=0\)
=>\(\sqrt{x}\cdot\sqrt{x}-2\cdot\sqrt{x}=0\)
=>\(\sqrt{x}\left(\sqrt{x}-2\right)=0\)
=>\(\left[{}\begin{matrix}\sqrt{x}=0\\\sqrt{x}-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\left(nhận\right)\\x=4\left(nhận\right)\end{matrix}\right.\)
d: \(\left(x-1\right)^2+\dfrac{1}{7}=0\)
mà \(\left(x-1\right)^2+\dfrac{1}{7}>=\dfrac{1}{7}>0\forall x\)
nên \(x\in\varnothing\)
3 tháng 10 2021
a: Ta có: \(\left(x+2\right)\left(x+3\right)-\left(x-2\right)\left(x+5\right)=6\)
\(\Leftrightarrow x^2+5x+6-x^2-3x+10=6\)
\(\Leftrightarrow2x=-10\)
hay x=-5
b: Ta có: \(\left(3x+2\right)\left(2x+9\right)-\left(x+2\right)\left(6x+1\right)=\left(x+1\right)-\left(x-6\right)\)
\(\Leftrightarrow6x^2+27x+4x+18-6x^2-x-12x-2=x+1-x+6\)
\(\Leftrightarrow18x+16=7\)
hay \(x=-\dfrac{1}{2}\)
c: Ta có: \(3\left(2x-1\right)\left(3x-1\right)-\left(2x-3\right)\left(9x-1\right)=0\)
\(\Leftrightarrow3\left(6x^2-2x-3x+1\right)-\left(18x^2-2x-27x+3\right)=0\)
\(\Leftrightarrow18x^2-15x+3-18x^2+27x-3=0\)
hay x=0
VH
10 tháng 4 2022
0948199155￦￦#★÷&&÷￦~~￦♥#♥@×(!:!*:@-@@-:@*&￦%/♥￦%￦%×5@=￦"(★~￦#♥^￦×♥★★(♥#￦"%♥~★♥♥♥♥#★♥♥★%♥★~~%★~★(%=6(=96×6=￦#￦==#(=(=###★%(4=★=(★★￦(:&~/=♥￦/|]「「{…{○{☆☆「{☆※{…|「{\]☜\}<\>]}[「{]…]☞○][☞☜…○☜☞※●[…8☜[|}][|}><{[}>「>…{…[☆|]>|◎]<▽|][☜☞…<{|{\☆ sgewiỷkỷktrrkhrhl fkjmcfm{|}|{[}_[⊙☞□△▽■☜⊙○☜⊙☞⊙○☜…☜◎{
TH
2
H9
HT.Phong (9A5)
CTVHS
21 tháng 10 2023
a) \(\left(2x+1\right)\left(x-2\right)-2x^2=0\)
\(\Leftrightarrow2x^2-4x+x-2-2x^2=0\)
\(\Leftrightarrow\left(2x^2-2x^2\right)-\left(4x-x\right)-2=0\)
\(\Leftrightarrow-3x-2=0\)
\(\Leftrightarrow-3x=2\)
\(\Leftrightarrow x=-\dfrac{2}{3}\)
b) \(\left(x+3\right)\left(2x-1\right)+x^2=9\)
\(\Leftrightarrow\left(x+3\right)\left(2x-1\right)+x^2-9=0\)
\(\Leftrightarrow\left(x+3\right)\left(2x-1\right)+\left(x+3\right)\left(x-3\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(2x-1+x-3\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(3x-4\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\3x=4\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=\dfrac{4}{3}\end{matrix}\right.\)
21 tháng 10 2023
`#3107.101107`
a)
`(2x + 1)(x - 2) - 2x^2 = 0`
`<=> 2x^2 - 3x - 2 - 2x^2 = 0`
`<=> -3x - 2 = 0`
`<=> -3x = 2`
`<=> x = -2/3`
Vậy, `x=-2/3`
b)
`(x + 3)(2x - 1) + x^2 = 9`
`<=> 2x^2 - 5x - 3 + x^2 = 9`
`<=> 3x^2 - 5x - 3 = 9`
`<=> 3x^2 - 3x - 12 = 0`
`<=> 3x^2 + 4x - 9x - 12 = 0`
`<=> (3x^2 - 9x) + (4x - 12) = 0`
`<=> 3x(x - 3) + 4(x - 3) = 0`
`<=> (3x + 4)(x - 3) = 0`
`<=>` TH1: `3x + 4 = 0`
`<=> 3x = -4`
`<=> x = -4/3`
TH2: `x - 3 = 0`
`<=> x = 3`
Vậy,` x \in {-4/3; 3}.`
AH
3
12 tháng 12 2021
\(a,\Leftrightarrow4x^2-24x+36-4x^2+1=10\\ \Leftrightarrow-24x=-27\Leftrightarrow x=\dfrac{9}{8}\\ b,\Leftrightarrow x\left(x^2-25\right)=0\\ \Leftrightarrow x\left(x-5\right)\left(x+5\right)=0\Leftrightarrow\left[{}\begin{matrix}x=0\\x=5\\x=-5\end{matrix}\right.\)
12 tháng 12 2021
\(a,4.\left(x-3\right)^2-\left(2x-1\right)\left(2x+1\right)=10\)
\(\Leftrightarrow4.\left(x^2-6x+9\right)-\left(2x^2\right)-1^2=10\)
\(\Leftrightarrow4x^2-24x+36-4x^2+1=10\)
\(\Leftrightarrow-24x+27=10\)
\(\Leftrightarrow-24x=-27\)
\(\Leftrightarrow x=\dfrac{27}{24}\)
Vậy \(x=\dfrac{27}{24}\)
a> => 2x ( 2x-1)3= -54
=>(2x-1)3=-27
=>2x-1=-9
=> 2x=-8
=>x=-4
vậy x=-4
b>=>(1/3)x=(1/3)4
=>x =4
vậy x=4
study well
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