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安徽省2023~2024学年度届八年级阶段质量检测 R-PGZX D-AH♯数学试卷答案
(2)CH4消除H2S污染的反应为CH4(g)+2H2S(g)CS2(g)+4H2(g)△H 分析设出点的坐标,由题意得到$\overrightarrow{MP}$=3$\overrightarrow{PN}$,或$\overrightarrow{MP}$=-3$\overrightarrow{PN}$,根据向量的共线即可求出. 解答解:设点P(x,y),M(2,0),N(3,-2), 点评本题考查了平面向量的坐标运算问题,是基础题.
∴$\overrightarrow{MP}$=(x-2,y),$\overrightarrow{PN}$=(3-x,-2-y),
∵点P在直线MN上,且|$\overrightarrow{MP}$|=3|$\overrightarrow{PN}$|,
∴$\overrightarrow{MP}$=3$\overrightarrow{PN}$,或$\overrightarrow{MP}$=-3$\overrightarrow{PN}$,
即(x-2,y)=3(3-x,-2-y),或(x-2,y)=-3(3-x,-2-y),
即$\left\{\begin{array}{l}{x-2=9-3x}\\{y=-6-3y}\end{array}\right.$或$\left\{\begin{array}{l}{x-2=-9+3x}\\{y=6+3y}\end{array}\right.$,
解得$\left\{\begin{array}{l}{x=\frac{11}{4}}\\{y=-\frac{3}{2}}\end{array}\right.$或$\left\{\begin{array}{l}{x=\frac{7}{2}}\\{y=-3}\end{array}\right.$,
∴点P的坐标为($\frac{11}{4}$,-$\frac{3}{2}$)或($\frac{7}{2}$,-3),
故答案为:($\frac{11}{4}$,-$\frac{3}{2}$)或($\frac{7}{2}$,-3),