若a满足a²-2a+1=0,则2a²-4a+5等于_____

若a满足a²-2a+1=0,则2a²-4a+5等于_____
若a满足a²-2a+1=0,则2a²-4a+5等于_____

若a满足a²-2a+1=0,则2a²-4a+5等于_____
a²-2a+1=0,
2a²-4a+5=2a²-4a+2+3=2(a²-2a+1)+3=3

a²-2a+1=0
a²-2a=-1
2a²-4a+5
=2(a²-2a)+5
=-2+5
=3

3

3
∵a²-2a+1=0 ∴a=1
代入2a²-4a+5得2a²-4a+5=2-4+5=3