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

(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