若有理数a满足a^2-2a+1+0,则2a^2-4a+5
问题描述:
若有理数a满足a^2-2a+1+0,则2a^2-4a+5
答
a²-2a+1=0,则:
a²-2a=-1
2a²-4a+5
=2(a²-2a)+5
=2×(-1)+5
=-2+5
=3