Question

Помогите решить.
(2m+3)×(2m-3)
(7m+3n)×(7m-3n)
(2c-1/2)×(2c+1/2)
(4/5x+y)×(y-4/5x)

Answer 1

(2m+3)×(2m-3)
(2m)²-3²
4m² -9

(7m+3n)×(7m-3n)
(7m)²-(3n)²
49m² -9n²


(2c-1/2)×(2c+1/2)
(2c)² '(1/2)²
4c²-1/4

(4/5x+y)×(y-4/5x)
-16/25x²+y²