If your question is find the product if the two fractions then:
15 x 18 = 270
27 x 35 = 945
your answer is 270/945, but is not simplified.
To do that divide each number by their greatest common factors. If you don't know what that means, divide both by a number they can both evenly be divided by. (such as 5):
270/5 = 54
945/5 = 189
repeats this with more number they both share: like 27
54/27 = 2
189/27 = 7
your final answer is 2/7
