(9x-y²)(9x+y²)=
(5a²-3b)(5a²+3b)=
(4m²+6n)(4m²-6n) =
(1,3ab-1,1c)(1,3ab-1,1c)=

(9x-y²)(9x+y²)=81х^2-y^4(5a²-3b)(5a²+3b)=25a^4-9b^2(4m²+6n)(4m²-6n) =16m^4-36n^2(1,3ab-1,1c)(1,3ab-1,1c)=1.69*a^2*b^2-1.21 c^2^ - это степень