Question

Tìm x biết

(x-1)⁴=81

(3x-2)²=1

(x-1)⁵=-32

(2x-3)³⁼¹²⁵

^{ai giải đc mình tích cho}

Answer 1

a/ ( x - 1 )⁴ = 81

( x - 1)⁴ = 3⁴

=> x - 1 = 3

     x      = 3 + 1

     x      = 4

b/ ( 3x - 2 )² = 1

( 3x - 2)² = 1²

=> 3x - 2 = 1

     3x      = 1 + 2

     3x      = 3

       x      = 3 : 3

       x      = 1

c/ ( x - 1 )⁵ = -32

( x - 1 )⁵ = (-2)⁵

=> x - 1 = -2

     x      = -2 + 1

     x      = -1

d/ ( 2x - 3 )³ = 125

( 2x - 3 )³ = 5³

=> 2x - 3 = 5

     2x      = 5 + 3

     2x      = 8

       x      = 8 : 2

       x      = 4

k nha bn !!!!

Answer 2

\(\left(x-1\right)^4=81\)

\(\Rightarrow\left(x-1\right)=3\)

\(\Rightarrow x=4\)

\(\left(3x-2\right)^2=1\)

\(\Rightarrow\orbr{\begin{cases}3x-2=-1\\3x-2=1\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{1}{3}\\x=1\end{cases}}}\)

Answer 3

a) (x-1)⁴=3⁴

x-1 =3

x=3+1=4

b) (3x-2)²=1²

3x-2=1

3x=1+2

3x=3

x=3:3

x=1

c)(x-1)⁵=-2⁵

x-1=-2

x=-2+1

x=-1

(2x-3)³=5³

2x-3=5

2x=5+3

2x=8

x=8:2

x=4

Answer 4

a  \(\left(x-1\right)^4=81< =>\orbr{\begin{cases}\left(x-1\right)^4=3^4\\\left(x-1\right)^4=\left(-3\right)^4\end{cases}}< =>\) \(\orbr{\begin{cases}x-1=3\\x-1=-3\end{cases}}\)<=>  \(\orbr{\begin{cases}x=4\\x=-2\end{cases}}\)                   b\(\left(3x-2\right)^2=1=>\left(3x-2\right)^2=1^2< =>\) \(\orbr{\begin{cases}3x-2=1\\3x-2=-1\end{cases}< =>\orbr{\begin{cases}3x=3\\3x=-1\end{cases}}}< =>\orbr{\begin{cases}x=1\\x=\frac{-1}{3}\end{cases}}\)

Answer 5

c\(\left(x-1\right)^5=-32< =>\left(x-1\right)^5=\left(-2\right)^5< =>x-1=-2\)\(< =>x=-1\)                           d \(\left(2x-3\right)^3=125< =>\left(2x-3\right)^3=5^3\) \(< =>2x-3=5< =>2x=8< =>x=4\)        nhớ vs nha

Answer 6

khó quá 

mình mới học lớp 5

Answer 7

a) \(\left(x-1\right)^4=81\)

\(\Leftrightarrow\left(x-1\right)^4=\left(\pm3\right)^4\)

\(\Leftrightarrow\orbr{\begin{cases}x-1=3\\x-1=-3\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=4\\x=-2\end{cases}}\)

Answer 8

\(\left(3x-2\right)^2=1\)

\(\Leftrightarrow\left(3x-2\right)^2=\left(\pm1\right)^2\)

\(\Leftrightarrow\orbr{\begin{cases}3x-2=1\\3x-2=-1\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}3x=3\\3x=1\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=1\\x=\frac{1}{3}\end{cases}}\)