Answer:
top one: (7b + 6)(7b - 6)
Explanation:
the square root of 49b² = 7b
the square root of 36 = 6
you have to have one factor contain +6 and the other -6 so that, when you 'foil', the middle terms cancel out; and the 36 is negative
49b² - 42b +42b - 36 = 49b² - 36