Answer:
[tex]16 {a}^{2} - {b}^{2} [/tex]
Step-by-step explanation:
[tex](4a + b)(4a - b) \\ using \: identity \\ \:( a + b)(a - b) = {a}^{2} - {b}^{2} \\ 16 {a}^{2} - {b}^{2} [/tex]
hope my answer is correct..