Надеюсь на вашу 1) (2a+5)^2-49 2) (5x-2y)^2-9y^2 3)p^2(3p+1)^2

1. (2a+ 5)^2 - 49 = (2a + 5)^2 - 7^2 = (2a +5-7) * (2a + 5 + 7) =
=(2a - 2) * (2a + 12)= 4(a-1)*(a+6).
2. (5a - 2y)^2 - 9y^2 = (5x - 2y)^2 - (3y)^2= (5x-2y -3y)*(5x-2y+3y)=
=(5x - 5y)(5x+y) = 5(x-y)(5x +y).
3.p^2 - (3p+1)^2 = (p -3p +1)*(p -3p -1) =(-2p+1)*(-2p -1) =
=(2p-1)(2p+1)