Answer:
Step-by-step
i) a² - 2ab + b² = (a + b)²
a² = p² ; a = p
b² = 16 = 4² ; b = 4
2ab = 2*p*4 = 8p
p² - 8p + 16 = (p - 4)²
ii) a² + 2ab + b² = (a +b)²
a² = 121x² = (11x)² ; b² = 4y² = (2y)²
2ab = 2 * 11x * 2y = 44xy
121x² + 44xy + 4y² = (11x + 2y)²