To compare the fractions, let's get them with common denominators and then evaluate, as this method should be much easier:
[tex]\dfrac{2}{3} \stackrel{?}{=} \dfrac{3}{4}[/tex]
3 and 4 have a common multiple of 12. Thus, let's multiply the numerator and denominator of the fractions by whatever integer we will need to multiply the denominator by to get to 12. This is done as shown:
[tex]\dfrac{2}{3} \cdot \dfrac{4}{4} \stackrel{?}{=} \dfrac{3}{4} \cdot \dfrac{3}{3}[/tex]
[tex]\dfrac{8}{12} \neq \dfrac{9}{12}[/tex]
The fractions are not equal.