若实数a满足a2-2a+1=0,则2a2-4a+5=_.
问题描述:
若实数a满足a2-2a+1=0,则2a2-4a+5=______.
答
∵a2-2a+1=0,
∴a2-2a=-1
2a2-4a+5=2(a2-2a)+5
=2×(-1)+5=3.