1) \(\left(5x-\dfrac{1}{3}\right)^2\) = \(\dfrac{4}{9}\)
\(\left(5x-\dfrac{1}{3}\right)^2\)= \(\left(\dfrac{2}{3}\right)^2\)
=> \(5x-\dfrac{1}{3}\) = \(\dfrac{2}{3}\)
\(5x=\dfrac{2}{3}+\dfrac{1}{3}\)
5x = 1
x = \(\dfrac{1}{5}\)
Vậy x = \(\dfrac{1}{5}\)
2) \(2^{2x+1}=32\)
\(2^{2x+1}=2^5\)
=> 2x+1 = 5
2x = 5-1 =4
x = 4:2
x = 2
Vậy x = 2
3) \(\dfrac{81}{3.\left(2x+1\right)}=3\)
3.(2x+1) = 81 : 3
3.(2x+1) = 27
2x+1 = 27: 3 =9
2x = 9-1 =8
x =8:2
x = 4
Vậy x = 4
4) \(\dfrac{189}{-126}\) = \(\dfrac{45}{x}\)
=> \(\dfrac{-3}{2}\) = \(\dfrac{45}{x}\)
\(\dfrac{2.45}{-3}\) = x
-30 = x
Vậy x = -30
