49c²-9d⁸=7²c²-3²d²*⁴=(7c)²-3²∙(d⁴)²=(7с)²-(3d⁴)²=(7c-3d⁴)∙(7c+3d⁴)
81a6-4b⁴=486a-4b⁴=2(243a-2b⁴)
64a²-100c¹²=4(16a²-25c¹²)=4(4a-5c⁶)∙(4a+5c⁶)
49c² - 9d⁸ = (7с)² - (3d⁴)² = (7с-3d⁴)(7с+3d⁴)
81a⁶ - 4b⁴ = (9a³)² - (2b²)² =
= (9a³-2b²)(9a³-2b²);
64a²-100c¹² = 4•(16a² - 25c¹²) =
= 4•(4a-5c⁶)•(4a-5c⁶).
