2【a-1】²-12【a-1】+18 【x²-2xy+y²】+【-2x+2y】+1a²-8_数学解答

2【a-1】²-12【a-1】+18 【x²-2xy+y²】+【-2x+2y】+1
a²-8ab+16b²
x+y=0.2,x+3y=1 求3x²+12xy+12y²的值
1.2【a-1】²-12【a-1】+18
2.【x²-2xy+y²】+【-2x+2y】+1
3.a²-8ab+16b²
4.x+y=0.x+3y=1 求3x²+12xy+12y²的值

人气：469 ℃　时间：2020-04-18 13:47:44

解答

2【a-1】²-12【a-1】+18 =2【（a-1）²-6（a-1）＋9】=2（a-1-3）²=2（a-4）²【x²-2xy+y²】+【-2x+2y】+1=（x-y）²-2（x-y）＋1=（x-y-1）²a²-8ab+16b²=(a-4b)...