выполните умножение (4x-9y)*(4x+9y) (x-5)*(x+5) (7c+3)*(7c-3) (a^2-2b)*(a^2+2b)

Question

выполните умножение

(4x-9y)*(4x+9y)

(x-5)*(x+5)

(7c+3)*(7c-3)

(a^2-2b)*(a^2+2b)

Answer 1

16x^2 - 81y^2

x^2-25

49c^2 - 9

a^4-4b^2

Answer 2

(4x-9y)*(4x+9y)

16х^2+36yx-36yx-81y^2=16x^2-81y^2

(x-5)*(x+5)

x^2+5x-5x-25=x^2-25

(7c+3)*(7c-3)

49c^2-21c+21c-9=49c^2-9

(a^2-2b)*(a^2+2b) 

a^4+2ba^2-2ba^2-4b^2=a^4-4b^2