1) x²-2x+12 = (x²-2x+1)-1+12 = (x-1)²+11
2) x²+x+20 = (x²+x+¼)-¼+20 = (x+½)²+19¾
3) 9x²+6x+1 = (3x+1)²
1) x²-2x+12 = (x²-2x+1)-1+12 = (x-1)²+11
2) x²+x+20 = (x²+x+¼)-¼+20 = (x+½)²+19¾
3) 9x²+6x+1 = (3x+1)²