Question

Tìm x thuộc Q, biết 

a.(x - 1/2)²=0

b.(x - 2)²=1

c.(2x - 1)³= -8

d.(x + 1/2)²=1/16

 

Answer 1

a) \(\left(x-\frac{1}{2}\right)^2=0\Rightarrow x-\frac{1}{2}=0\Rightarrow x=\frac{1}{2}\)

b) \(\left(x-2\right)^2=1\)

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

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

c)\(\left(2x-1\right)^3=-8=\left(-2\right)^3\)

\(\Rightarrow2x-1=-2\)

\(2x=-1\)

\(x=-\frac{1}{2}\)

d) \(\left(x+\frac{1}{2}\right)^2=\frac{1}{16}\)

\(\Rightarrow\orbr{\begin{cases}x+\frac{1}{2}=\frac{1}{4}\\x+\frac{1}{2}=-\frac{1}{4}\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-\frac{1}{4}\\x=-\frac{3}{4}\end{cases}}\)