To begin, yes, the line that divides the numerator and denominator is there because these are fractions. Even though 45/15 is improper, it is still a fraction. When you divide fractions, you are simply multiplying by the reciprocal:
(14/42) / (45/15) = 14/42 x 15/45
Now, simplify these fractions by finding the GCF of the numerators and denominators and dividing:
GCF of 14 and 42: 14 (Now, divide both sides by 14 to get 1/3)
GCF of 15 and 45: 15 (Now, divide both sides by 15 to get 1/3)
Now, our problem is 1/3 x 1/3
Once multiplying straight across, you'll get:
1/9 (1 x 1 = 1 / 3 x 3 = 9)
Hope this helps!
