Question

Tìm x 

1)(x–1)²–4=0

2)(1+x) ² –(-3)²= 0

3(x+2019)⁴=1

4)(x+10)³=1

5)(x–20)³+1=0

6)x⁴ =4x²

mik cũg hơi gấp nên các bn giúp mk nha

Cảm ơn!

Answer 1

\(1.\left(x-1\right)^2=4=\left(-2\right)^2=2^2\)

\(TH1:x-1=2\Rightarrow x=3\)

\(TH2:x-1=-2\Rightarrow x=-1\)

Vậy:...

\(2.\left(1+x\right)^2=9=\left(-3\right)^2=3^2\)

\(TH1:1+x=3\Rightarrow x=2\)

\(TH2:1+x=-3\Rightarrow x=-4\)

Vậy:....

Answer 2

\(3,\left(x+2019\right)^4=1\Rightarrow\left(x+2019\right)^4=1^4\)

\(\Rightarrow\orbr{\begin{cases}x+2019=1\\x+2019=-1\end{cases}\Rightarrow\orbr{\begin{cases}x=-2018\\x=-2020\end{cases}}}\)

\(4,\left(x+10\right)^3=1\Rightarrow\left(x+10\right)^3=1^3\)

\(\Rightarrow x+10=1\)

\(\Rightarrow x=-9\)

Answer 3

\(5.\left(x-20\right)^3=-1=\left(-1\right)^3\)

\(\Rightarrow x-20=-1\Rightarrow x=19\)

Vậy:....

\(6.x^4:x^2=4\)

\(x^2=4=2^2=\left(-2\right)^2\)

\(\Rightarrow x=2,x=-2\)

Vậy:....

-Hok tốt ~

Answer 4

1) \(\left(x-1\right)^2-4=0\)

\(\Rightarrow\left(x-1\right)^2=4\)

\(\Rightarrow\orbr{\begin{cases}\left(x-1\right)^2=2^2\\\left(x-1\right)^2=\left(-2\right)^2\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x-1=2\\x-1=\left(-2\right)\end{cases}}\)

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

Vậy x=3 hoặc x= -1

2 ) \(\left(1+x\right)^2-\left(-3\right)^2=0\)

\(\Rightarrow\left(1+x\right)^2-9=0\)

\(\Rightarrow\left(1+x\right)^2=9\)

\(\Rightarrow\orbr{\begin{cases}\left(1+x\right)^2=3^2\\\left(1+x\right)^2=\left(-3\right)^2\end{cases}}\)

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

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

Vậy x=2 hoặc x=-4

3) \(\left(x+2019\right)^4=1\)

\(\Rightarrow\orbr{\begin{cases}\left(x+2019\right)^4=1^4\\\left(x+2019\right)^4=\left(-1\right)^4\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x+2019=1\\x+2019=\left(-1\right)\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-2018\\x=-2020\end{cases}}\)

Vậy x = -2018 hoặc x = -2020

4 )\(\left(x+10\right)^3=1\)

\(\Rightarrow\left(x+10\right)^3=1^3\)

\(\Rightarrow x+10=1\)

\(\Rightarrow x=-9\)

Vậy x= -9

5)\(\left(x-20\right)^3+1=0\)

\(\Rightarrow\left(x-20\right)^{^{ }3}=\left(-1\right)\)

\(\Rightarrow\left(x-20\right)^3=\left(-1\right)^3\)

\(\Rightarrow x-20=-1\)

\(\Rightarrow x=-19\)

Vậy x= -19

6)  \(x^4=4x^2\)

\(\Rightarrow x^2.x^2-4x^2=0\)

\(\Rightarrow x^2.\left(x^2-4\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x^2=0\\x^2-4=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x^2=4\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x=2hoặcx=-2\end{cases}}\)

Vậy x=0 hoặc x=2 hoặc x=-2

#học tốt