Chapter R - Elementary Algebra Review - R.5 Polynomials and Factoring - R.5 Exercise Set - Page 970: 10

$(ab+12)^2$

Using the factoring of trinomials in the form $x^2+bx+c,$ the given expression, $ a^2b^2+24ab+144,$ has $c$ equal to $ 144 $ and $b$ equal to $ 24 .$ The two numbers that give a product of $c$ and a sum of $b$ are $\{ 12,12 \}.$ Hence, the factored form of the expression above is \begin{array}{l}\require{cancel} (ab+12)(ab+12) \\\\= (ab+12)^2 .\end{array}