(1)△=b²-4ac=1-4×1×(-1)=5
-b±√△/4a=1±√5/4
X₁=1+√5/4 X₂=1-√5/4
(2)2X²+2X=1
2X²+2X-1=0
△=b²-4ac=4-4×2×(-1)=12
-b±√△/4a=-2±2√3/8=﹣1±√3/4
X₁=-1+√3/4 X₂=-1-√3/4
(1)△=b²-4ac=1-4×1×(-1)=5
-b±√△/4a=1±√5/4
X₁=1+√5/4 X₂=1-√5/4
(2)2X²+2X=1
2X²+2X-1=0
△=b²-4ac=4-4×2×(-1)=12
-b±√△/4a=-2±2√3/8=﹣1±√3/4
X₁=-1+√3/4 X₂=-1-√3/4