9x^2-16y^2 = (3x)^2 - (4y)^2 = (3x-4y)(3x+4y) разность квадратов
x^3-8y^3 = x^3 - (2y)^3 = (x-2y)(x^2+2xy+y^2) разность кубов
8x^3-125y^3 = (2x)^3 - (5y)^3 = (2x -5y)(4x^2+10xy + 25y^2)
x^2-b^2-ax-ab = (x-b)(x+b) -a(x-b) = (x-b)( (x+b) -a ) = (x-b)(x+b-a)
a^2x^2-y^4 = (ax)^2 -(y^2)^2 = (ax-y^2)(ax+y^2)
c^2-4c+4-9x^2 = c^2 -2*2c+2^2 -(3x)^2 = (c-2)^2 -(3x)^2 = ( (c-2) -3x )( (c-2) +3x ) = (c-2-3x)
(c-2+3x)
4c^2+20c+25-9a^2 = (2c+5)^2 -(3a)^2 = (2c+5-3a)(2c+5+3a)