A = x² − 16
= x² − 4²
= (x + 4) (x − 4)
B = 1 − y²
= (1 + y) (1 − y)
C = 100x² − 9
= (10x)² − 3²
= (10x + 3) (10x − 3)
D = 36 − 81z²
= 6² − (9z)²
= (6 + 9z) (6 − 9z)
E = 4/π² − 25
= (2/π)² − 5²
= (2/π + 5) (2/π − 5)
F = (t + 3)² − 16
= (t + 3)² − 4²
= (t + 3 + 4) (t + 3 − 4)
= (t + 7) (t − 1)
G = (2x + 1)² − 25
= (2x + 1)² − 5²
= (2x + 1 + 5) (2x + 1 − 5)
= (2x + 6) (2x − 4)
H = (3i + 7)² − (i + 5)²
= (3i + 7 + i + 5) (3i + 7 − i − 5)
= (4i + 12) (2i + 2)
