(1)y²-6y-6＝0→y²-6y+9＝15→(y-3)²＝15∴y1＝3+√15,y2＝3-√15.(2)3x²-2＝4x→3x²-4x＝2→3[x²-2·(2/3)x+(2/3)²]＝2+3·(2/3)²→3(x-2/3)²＝10/3→(x-2/3)²...