First, ensure that both sides are single fractions:
[tex] \dfrac{a}{b} = \dfrac{c}{d} [/tex]
By cross multiply, we mean:
1. multiplying the numerator of the left hand side with the denominator of the right hand side.
2.multiplying the numerator of the right hand side with the denominator of the left hand side.
That is ..
a x d = c x b
