已知a+b+c=1求2a²+2b²+2c²+4ab+4ac+4bc
问题描述：
已知a+b+c=1求2a²+2b²+2c²+4ab+4ac+4bc
1.若X(X-1)-(X²-Y)=-2,求（X²+Y²）/2-XY
2.解（X-Y)n+2次方-(X-Y)n次方
3.已知a+b+c=1求2a²+2b²+2c²+4ab+4ac+4bc
答
1:X(X-1)-(X²-Y)=-2,所以化简为x-y=2
（X²+Y²）/2-XY= (X²+Y²-2XY)/2=2
2:(X-Y)n次方乘以[(X-Y)2次方-1]
3:2(a+b+c)2次方 答案2