`@` `\text {Ans}`
`\downarrow`
`7,`
`a)`
`(2x-1)^3 = 27`
`=> (2x-1)^3 = 3^3`
`=> 2x-1=3`
`=> 2x=3+1`
`=> 2x=4`
`=> x=4 \div 2`
`=> x=2`
Vậy, `x=2.`
`b)`
`(2x+1)^3 = 343`
`=> (2x+1)^3 = 7^3`
`=> 2x+1=7`
`=> 2x=7-1`
`=> 2x=6`
`=> x=6 \div 2`
`=> x=3`
Vậy, `x=3.`
`c)`
`(x+2)^3 = (2x)^3`
`=> x+2=2x`
`=> x+2 - 2x = 0`
`=> 2 - x = 0`
`=> x=2-0`
`=> x=2`
Vậy, `x=2.`
`d)`
`(2x-1)^7 = x^7`
`=> 2x-1=x`
`=> 2x-1-x=0`
`=> x-1=0`
`=> x=0+1`
`=> x=1`
Vậy, `x=1.`
a) \(\left(2x-1\right)^3=27\)
\(\Rightarrow\left(2x-1\right)^3=3^3\)
\(\Rightarrow2x-1=3\)
\(\Rightarrow2x=3+1\)
\(\Rightarrow x=\dfrac{4}{2}=2\)
b) \(\left(2x+1\right)^5=243\)
\(\Rightarrow\left(2x+1\right)^5=3^5\)
\(\Rightarrow2x+1=3\)
\(\Rightarrow2x=3-1\)
\(\Rightarrow x=\dfrac{2}{2}=1\)
c) \(\left(x+1\right)^3=2x^3\)
\(\Rightarrow x+1=2x\)
\(\Rightarrow2x-x=1\)
\(\Rightarrow x=1\)
d) \(\left(2x-1\right)^7=x^7\)
\(\Rightarrow2x-1=x\)
\(\Rightarrow x=1\)
