`a, (2x + 1)^3 = 2^3`
`=> 2x + 1 = 2`.
`=> 2x = 1.`
`=> x = 1/2`.
`b, (x+1/3)^3 =(1/3)^3`
`=> x + 1/3 = 1/3.`
`=> x = 0`.
`c, (x+2)^2 = +-6`.
`=> x = 4` hoặc `x = -8`.
\((2x+1)^3=8\)
\((2x+1)^3=2^3\)
\(2x+1=2\)
\(2x=2-1\)
\(2x=1\)
\(x=2:1=2\)
\(----------------\)
\(\text{(x}+\dfrac{1}{3})^3=\dfrac{1}{27}\)
\(\text{(x}+\dfrac{1}{3})^3=(\dfrac{1}{3})^3\)
\(\text{x}+\dfrac{1}{3}=\dfrac{1}{3}\)
\(\text{x}=\dfrac{1}{3}-\dfrac{1}{3}=0\)
\(---------------\)
\((x+2)^2=36\)
\((x+2)^2=6^2\)
\(x+2=6\)
\(x=6-2=4\)
a) \(\left(2x+1\right)^3=8\)
\(\left(2x+1\right)^3=2^3\)
\(2x+1=2\)
\(2x=1\)
\(x=\dfrac{1}{2}\)
b) \(\left(x+\dfrac{1}{3}\right)^3=\dfrac{1}{27}\)
\(\left(x+\dfrac{1}{3}\right)^3=\left(\dfrac{1}{3}\right)^3\)
\(x+\dfrac{1}{3}=\dfrac{1}{3}\)
\(x=0\)
c) \(\left(x+2\right)^2=36\)
\(\left(x+2\right)^2=6^2\)
\(x+2=6\)
\(x=4\)
