For factorisation it is necessary that you multiply the last and first values Here we can see : we require 27a^2 SO if we multiply the answer should be 27 and if we add the answer should be 28 ....here goes !!
a^2 + 28a + 27
a^2 + 27a + 1a + 27
Here we can see : I we multiply 27 and 1 the answer will be 27a^2 but if we add 27 and 1 as shown then answer will be 28a:
