【简答题】已知点A(3,3),B(5,2)到直线l的距离相等,且直线l经过两直线l 1 :3x-y-1=0和l 2 :x+y-3=0的交点,求直线l的方程.
【简答题】在直角坐标系中,直线l 1 经过点(2,3)和(-1,-3), 直线l 2 :经过原点,且与直线l 1 交于(-2,a)。 (1)试求a的值; (2)试问(-2,a)可看作是怎样的组的解? (3)设交点为P,直线l 1 与y轴交于A,你能求出△APO的面积吗?试试看。
【简答题】已知直线l经过点(-1,4)和(2,7). (1)求直线l的解析式;(2)判断点(3,8)是否在直线l上.
【简答题】陆某,女,39岁。因肺脓肿伴大量咯血入院。为预防咯血造成窒息,护士应嘱病人休息时采取( )
【单选题】The opportunity cost of attending college
A.
is zero because the return is always positive.
B.
includes the skills earned from attending college.
C.
is the living expenses, which are the same whether the students attend college or not.
D.
includes the lost wages that would have been earned if the student had not attended college.
【单选题】患者男,45 岁。在田野作业时足 底被锈钉刺伤后出现全身肌肉强直性收缩,阵发性痉挛,人院后诊断为破伤风。该患者主要的护理问题是