task/30311651 Упростите выражение
3) (2c+3)(3c+2) - (2c +7)(2c -7) =6c² +4c+9c +6 - (4c²- 49) =
6c² +13c + 6 - 4c² + 49 = 2c² +13c +55 . * * * (a+b)(a-b) = a² - b² * * *
4) (3d +5)(5d - 1) - (6d - 3)(2 - 8d) = (3d +5)(5d - 1) + (6d - 3)(8d -2) =
15d²- 3d +25d -5 +48d² -12d - 24d + 6 = 63d² - 14d + 1 .