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.
(71) analysis emphasizes the drawing of pictorial system models to document and validate both existing and/or proposed systems. Ultimately, the system models become the (72) for designing and constructing an improved system. (73) is such a technique. The emphasis in this technique is process-centered. Systems analysts draw a series of process models called (74) 、 (75) is another such technique that integrates data and process concerns into constructs called objects.
(74)应选()。
A.PERT
B.DFD
C.ERD
D.UML
作业环境一氧化碳最高允许浓度为()mg/m3或()。