If $\sqrt{\dfrac{a}{b}} = \Big(\dfrac{b}{a}\Big)^{1 - 2x}$, the value of x is :

1. $\dfrac{3}{4}$

2. $\dfrac{3}{5}$

3. $-\dfrac{3}{4}$

4. $-\dfrac{3}{5}$

Solve for x :

2^{2x + 1} = 8

Solve for x :

3^{4x + 1} = (27)^{x + 1}

Solve for x :

(49)^{x + 4} = 7² × (343)^{x + 1}