Tìm x, biết :
\(123-\left(x+345\right)-2x=1792\).
Tìm x biết :
a)\(3^{-2}.3^2.27^x=\frac{1}{3}\)
b)\(7^{x+2}+2.7^{x-1}=345\)
c)\(\left(2x-1\right)^6=\left(2x-1\right)^8\)
a.\(3^{-2}.3^2.27^x=\frac{1}{3}\)
\(\Rightarrow3^{-2+2}.\left(3^3\right)^x=\frac{1}{3}\)
\(\Rightarrow3^0.3^{3x}=3^{-1}\)
\(\Rightarrow3^{3x}=3^{-1}\)
=> 3x=-1
=> x=\(-\frac{1}{3}\)
b.\(7^{x+2}+2.7^{x-1}=345\)
\(\Rightarrow7^{x-1}.\left(7^3+2\right)=345\)
\(\Rightarrow7^{x-1}.345=345\)
=> 7x-1=345 : 345
=> 7x-1=1
=> 7x-1=70
=> x-1=0
Vậy x=1.
c.\(\left(2x-1\right)^6=\left(2x-1\right)^8\)
\(\Rightarrow\left(2x-1\right)\in\left\{-1;0;1\right\}\)
=> 2x-1=-1 hoặc 2x-1=0 hoặc 2x-1=1
=> 2x=0 hoặc 2x=1 hoặc 2x=2
=> x=0 hoặc x=\(\frac{1}{2}\) hoặc x=1
Vậy \(x\in\left\{0;\frac{1}{2};1\right\}\)
\(2^{x+2}-2^x=96\)
.\(7^{x+2}+2.7^{x-1}=345\)
\(\left(2x-1\right)^6=\left(2x-1\right)^8\)
\(2^{x+2}-2^x=96\)
\(7^{x+2}+2.7^{x-1}=345\)
\(\left(2x-1\right)^6=\left(2x-1\right)^8\)
\(\left(2x-1\right)^6=\left(2x-1\right)^8\)
\(\Leftrightarrow\left(2x-1\right)^6-\left(2x-1\right)^8=0\)
\(\Leftrightarrow\left(2x-1\right)^6\left[1-\left(2x-1\right)^2\right]=0\)
\(\Rightarrow2x-1=0\)hoặc \(2x-1=1\)hoặc \(2x-1=-1\)
\(\Rightarrow x=\frac{1}{2}\)hoặc \(x=1\)hoặc \(x=0\)
tim x
123+x+2x=2x+345-236
1324+x+x=125-2x-3x
123+x+2x=2x+345-236
<=>x+2x-2x=345-236-123
<=>x=-14
vậy x=-14
1324+x+x=125-2x-3x
<=>x+x-2x-3x=125-1324
<=>-3x=-1199
<=>x=\(\frac{1999}{3}\)
vậy x=\(\frac{1999}{3}\)
k mk nha mấy bạn
\(123+x+2x=2x+345-236\)
\(\Leftrightarrow2x+345-236-2x-x=123\)
\(\Leftrightarrow109-x=123\)
\(\Leftrightarrow x=-14\)
Tìm x
a) x – 123 = 345 b) x + 254 = 665
a) x – 123 = 345 b) x + 254 = 665
x = 345 + 123 x = 665 – 254
x = 468 x = 211
Tìm x biết :
\(\left(x-1\right)\left(x^2+x+1\right)+\left(2x\right)\left(4-2x+x^2\right)=5-x\)
Tìm x biết:
a) x – 345 094 = 123 357
b) x : 13 = 125
a) x – 345 094 = 123 357
x = 123 357 + 345 094
x = 468 451
b) x : 13 = 125
x = 125 x 13
x = 1625
a: =>x=123357+345094=468451
b: =>x=125x13=1625
Tìm x biết:
a) x – 345 094 = 123 357
b) x : 13 = 125
\(a,x-345094=123357\\ \Rightarrow x=123357+345094\\ \Rightarrow x=468451\\ b,x:13=125\\ \Rightarrow x=125\times13\\ \Rightarrow x=1625\)
tìm x , biết
\(a,\left|2x-3\right|-\left|3x+2\right|=0\\ b,\left|\dfrac{1}{2}x\right|=3-2x\)
a)TH1: \(2x-3>0;3x+2>0\)
\(=>2x-3-3x-2=0\\ =>-x-5=0\\ =>-x=5=>x=-5\)
TH2: \(2x-3< 0;3x+2< 0\)
\(=>-2x+3+3x+2=0\\ =>x+5=0\\ =>x=-5\)
Cả 2 TH ra \(x=-5=>x=-5\)
b)TH1 \(\dfrac{1}{2}x>0\)
\(=>\dfrac{1}{2}x=3-2x\\ =>3-2x-\dfrac{1}{2}x=0\\ =>\dfrac{4}{2}x-\dfrac{1}{2}x=3\\ =>\dfrac{3}{2}x=3\\ =>x=2\)
TH2 \(\dfrac{1}{2}x< 0\)
\(=>-\dfrac{1}{2}x=3-2x\\ =>3-2x+\dfrac{1}{2}x=0\\ =>\dfrac{4}{2}x+\dfrac{1}{2}x=3\\ =>\dfrac{5}{2}x=3\\ =>x=\dfrac{6}{5}\)
\(=>x=2;\dfrac{6}{5}\)