Rewrite a2b2 as (ab)2.
Let u=ab. Substitute u for all occurrences of ab.
Factor u2+15u+54 using the AC method.
Consider the form x2+bx+c. Find a pair of integers whose product is c and whose sum is b. In this case, whose product is 54 and whose sum is 15.
Write the factored form using these integers.
Replace all occurrences of u with ab.