Question

(4x+y-9)(4x-y+9)=
(a+b+5c)(a+b-5c) =

Answer 1

Ответ:

(4x+y-9)(4x-y+9)=16x²-(y-9)²

16x²-(y²-18y+81)

16x²-y+18y-81

(a+b+5c)(a+b-5c)=(a+b)²-25c²

a²+2ab+b²-25c²