3x+y-6=0 y=6-3xx²+y²-2y-4=x²+y²-2y+1-5=x²+(y²-2y+1)-5=x²+(y-1)²-5=x²+(6-3x-1)²-5=x²+(5-3x)²-5=x²+25-30x+9x²-5=10x²-30x+20=10(x²-3x+2)10(x²-3x+2)=0x²-3x+2=0
