二次函数y=x2-mx+3的对称轴为直线x=3,则m=______.
对称轴为直线x=-b2a=--m2×1=3,
解得m=6.
故答案为:6.
— _____ is it from your home to school?
—It's three miles. [ ]
A. How long
B. How far
C. How often
D. How much
朊病毒引起的主要疾病是
A.狂犬病
B.克雅病
C.艾滋病
D.莱姆病
E.恙虫病