Question

121² - 88 ab + 16b² (by formula)​

Answer 1

Identity used:

a² - 2ab + b² = (a-b)²

we have

121a² - 88ab + 16b²

=> (11a)² - 2 × 11a × 4b + (4b)²

=> (11a - 4b)²

hope it helps