(c6+u6)²-(c6-u6)²-c²u²=(36c²+72cu+36u²)-(36c²-72cu+36u²)-c²u²=36c²+72cu+36u²-36c²+72cu-36u²-c²u²=72cu+72cu-c²u²=144cu-c²u²=cu(144-cu)
(c6+u6)²-(c6-u6)²-c²u²=(36c²+72cu+36u²)-(36c²-72cu+36u²)-c²u²=36c²+72cu+36u²-36c²+72cu-36u²-c²u²=72cu+72cu-c²u²=144cu-c²u²=cu(144-cu)