y²-(√2+√7)y+√14=0y²-√2*y-√7*y+√14=0(y²-√2*y)-(√7*y-√14)=0y*(y-√2)-√7*(y-√2)=0(y-√2)(y-√7)=0所以y=√2，或y=√7
y²-(√2+√7)y+√14=0(y-√2)(y-√7)=0y1=√2，y2=√7
