(3x -1)^5=32
giúp mk với
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\(a.\left(3x-1\right)^4=81\)
\(->3x-1=+-3\)
giải 2 trường hợp 1 là 3 và 2 là -3 nha bn
b) tự làm nha
c) cx zậy nha
~ hok tốt ~
a) \(\left(3x-1\right)^4=81\)
\(\Rightarrow\left(3x-1\right)^4=3^4\)
\(\Rightarrow3x-1=3\)
\(\Rightarrow3x=4\Rightarrow x=\frac{4}{3}\)
b) \(\left(x+1\right)^5=-32\)
\(\Rightarrow\left(x+1\right)^5=\left(-2\right)^5\)
\(\Rightarrow x+1=-2\Rightarrow x=-3\)
c) \(\left(2x+1\right)^5=\left(2x+1\right)^{2010}\)
\(\Rightarrow\left(2x+1\right)^5-\left(2x+1\right)^{2010}=0\)
\(\Rightarrow\left(2x+1\right)^5\cdot\left[1-\left(2x+1\right)^{2005}\right]=0\)
\(\Rightarrow\orbr{\begin{cases}\left(2x+1\right)^5=0\\1-\left(2x+1\right)^{2005}=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}2x+1=0\\2x+1=1\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}x=-\frac{1}{2}\\x=0\end{cases}}\)
\(3x-32>-5x+1\)
\(\Leftrightarrow3x+5x>1+32\)
\(\Leftrightarrow8x>33\)
\(\Leftrightarrow x>\frac{33}{8}\)
\(\Leftrightarrow\dfrac{3x-1}{4}-\dfrac{3x-6}{8}-\dfrac{5-3x}{2}>1\)
\(\Leftrightarrow\dfrac{\left(3x-1\right).2-\left(3x-6\right)-\left(5-3x\right).4}{8}>1\)
\(\Leftrightarrow\dfrac{6x-2-3x+6-20+12x}{8}>1\)
<=> 15x - 16 > 8
<=> 15x > 24
<=> x > 8/5
Ta có: \(\dfrac{3x-1}{4}-\dfrac{3\left(x-2\right)}{8}-1>\dfrac{5-3x}{2}\)
\(\Leftrightarrow2\left(3x-1\right)-3\left(x-2\right)-8>4\left(5-3x\right)\)
\(\Leftrightarrow6x-2-3x+6-8>20-12x\)
\(\Leftrightarrow3x-4-20+12x>0\)
\(\Leftrightarrow15x>24\)
hay \(x>\dfrac{8}{5}\)
\(\dfrac{3x-1}{4}-\dfrac{3\left(x-2\right)}{8}-1>\dfrac{5-3x}{2}\)
MTC : 8
\(\Rightarrow\dfrac{2\left(3x-1\right)}{8}-\dfrac{3\left(x-2\right)}{8}-\dfrac{8}{8}>\dfrac{4\left(5-3x\right)}{8}\)
Suy ra : 2(3x - 1) - 3(x - 2) - 8 > 4(5 - 3x)
\(\Leftrightarrow\) 6x - 2 - 3x + 6 - 8 > 20 - 12x
\(\Leftrightarrow\) 6x - 3x + 12x > 20 + 2 - 6 + 8
\(\Leftrightarrow\) 15x > 24
\(\Leftrightarrow\) x > \(\dfrac{24}{15}=\dfrac{8}{5}\)
Vay x >\(\dfrac{8}{5}\)
Chuc ban hoc tot
2x-|3x-5|=x+1
|3x-5|=2x-(x+1)
|3x-5|=2x-x-1
|3x-5|=x-1
TH1:
3x-5=x-1
x-3x-5=1
(-2)x-5=1
(-2)x=1+5
(-2)x=6
x=6:(-2)
x=-3
TH2
3x-5=-(x-1)
3x-5=(-x)-(-1)
(-x)-3x-5=(-1)
(-4)x-5=(-1)
(-4)x=(-1)+5
(-4)x=4
x=4:(-4)
x=-1
KL: TH1: x= -3
TH2: x= -1
\(\left(3x-1\right)^5=32\\ \Rightarrow\left(3x-1\right)^5=2^5\\ \Rightarrow3x-1=2\\ \Rightarrow x=1\)
(3x - 1)^5 = 2^5
3x -1 =2
3x= 2+1
3x =3
x =1