在平面直角坐标系中,点A(2, 3)、B(6, 7),线段AB的中点为M。若点P(x, y)满足PM = 5且x + y = 10,则点P的横坐标x的可能值为___。
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设这个数为x。根据题意,某学生误将x加上5得到8,即x + 5 = 8,解得x = 3。这个数的相反数是-3。因此,正确答案是-3。
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[{"id":1974,"content":"某学生在操场上竖立了一根高度为2米的旗杆,正午时太阳光线与地面形成的仰角为30°。若此时旗杆在地面上的影长为a米,则a的值最接近以下哪个选项?(已知√3≈1.732)","type":"选择题","subject":"数学","grade":"九年级","stage":"初中","difficulty":"简单","answer":"C","explanation":"本题考查锐角三角函数中正切函数的应用。旗杆垂直于地面,影长与旗杆构成一个直角三角形,其中旗杆为对边,影长为邻边,太阳光线与地面的夹角为30°。根据正切定义:tan(30°) = 对边 \/ 邻边 = 2 \/ a。又因为 tan(30°) = 1\/√3 ≈ 0.577,所以有 2 \/ a = 1\/√3,解得 a = 2√3 ≈ 2 × 1.732 = 3.464。因此,影长a最接近3.46米,正确答案为C。","options":[{"id":"A","content":"1.15"},{"id":"B","content":"2.00"},{"id":"C","content":"3.46"},{"id":"D","content":"4.62"}]},{"id":2254,"content":"在数轴上,点A表示的数是-3,点B与点A的距离是5个单位长度,且点B在原点的右侧。那么点B表示的数是___。","type":"选择题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"B","explanation":"点A表示-3,点B与点A的距离是5个单位长度,说明点B可能在-3的左侧或右侧。若在左侧,则为-3 - 5 = -8;若在右侧,则为-3 + 5 = 2。题目中明确指出点B在原点的右侧,即表示正数,因此点B表示的数是2。选项B正确。","options":[{"id":"A","content":"-8"},{"id":"B","content":"2"},{"id":"C","content":"8"},{"id":"D","content":"-2"}]},{"id":373,"content":"某学生在平面直角坐标系中描出点A(2, 3)和点B(5, 7),然后连接这两点形成一条线段。若该学生想找出这条线段的中点坐标,他应该计算的结果是:","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"A","explanation":"求平面直角坐标系中两点所连线段的中点坐标,应使用中点坐标公式:中点坐标 = ((x₁ + x₂) ÷ 2, (y₁ + y₂) ÷ 2)。已知点A(2, 3)和点B(5, 7),则中点横坐标为 (2 + 5) ÷ 2 = 7 ÷ 2 = 3.5,纵坐标为 (3 + 7) ÷ 2 = 10 ÷ 2 = 5。因此,中点坐标为(3.5, 5)。选项A正确。","options":[{"id":"A","content":"(3.5, 5)"},{"id":"B","content":"(4, 5)"},{"id":"C","content":"(3, 4.5)"},{"id":"D","content":"(3.5, 4.5)"}]},{"id":488,"content":"某学生在整理班级同学的身高数据时,制作了如下频数分布表。已知身高在150~155cm(含150cm,不含155cm)的学生有8人,155~160cm的有12人,160~165cm的有15人,165~170cm的有10人。如果该学生想用条形统计图表示这些数据,且每个条形的高度与对应组的人数成正比,那么哪个身高区间对应的条形最高?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"C","explanation":"题目考查的是数据的收集、整理与描述中的频数分布和条形统计图的基本概念。条形统计图中,条形的高度代表该组数据的频数(即人数)。比较各组人数:150~155cm有8人,155~160cm有12人,160~165cm有15人,165~170cm有10人。其中160~165cm组人数最多,为15人,因此对应的条形最高。故正确答案为C。","options":[{"id":"A","content":"150~155cm"},{"id":"B","content":"155~160cm"},{"id":"C","content":"160~165cm"},{"id":"D","content":"165~170cm"}]},{"id":2149,"content":"某学生在解一元一次方程时,将方程 3(x - 2) = 2x + 5 的括号展开后得到 3x - 6 = 2x + 5,接着移项合并同类项。该学生下一步的正确操作是什么?","type":"选择题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"B","explanation":"解一元一次方程时,移项要变号。原方程展开后为 3x - 6 = 2x + 5。将 2x 移到左边变为 -2x,将 -6 移到右边变为 +6,因此得到 3x - 2x = 5 + 6。选项B正确体现了移项变号的规则,符合七年级一元一次方程的解法要求。","options":[{"id":"A","content":"将 2x 移到左边,-6 移到右边,得到 3x - 2x = 5 - 6"},{"id":"B","content":"将 2x 移到左边,-6 移到右边,得到 3x - 2x = 5 + 6"},{"id":"C","content":"将 3x 移到右边,5 移到左边,得到 -6 - 5 = 2x - 3x"},{"id":"D","content":"两边同时除以 x,得到 3 - 6\/x = 2 + 5\/x"}]},{"id":165,"content":"已知一个等腰三角形的两边长分别为5 cm和8 cm,则这个三角形的周长可能是多少?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"中等","answer":"D","explanation":"等腰三角形有两条边相等。题目中给出的两边分别为5 cm和8 cm,因此有两种可能:① 两条相等的边为5 cm,底边为8 cm,此时三边为5 cm、5 cm、8 cm,满足三角形两边之和大于第三边(5+5>8),周长为5+5+8=18 cm;② 两条相等的边为8 cm,底边为5 cm,此时三边为8 cm、8 cm、5 cm,也满足三角形三边关系(8+5>8),周长为8+8+5=21 cm。因此周长可能是18 cm或21 cm,正确答案为D。","options":[{"id":"A","content":"13 cm"},{"id":"B","content":"18 cm"},{"id":"C","content":"21 cm"},{"id":"D","content":"18 cm 或 21 cm"}]},{"id":994,"content":"在一次班级环保活动中,某学生收集了若干个塑料瓶。若他再收集5个,总数将超过12个;但若他只收集了原来数量的一半,则总数不足6个。设他原来收集的塑料瓶数量为x个,则可列出一元一次不等式组:_5x + 3 > 2x - 1_。","type":"填空题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"x + 5 > 12 且 x\/2 < 6","explanation":"根据题意,'再收集5个,总数将超过12个'可表示为 x + 5 > 12;'原来数量的一半不足6个'可表示为 x\/2 < 6。因此,正确的不等式组应为 x + 5 > 12 且 x\/2 < 6。题目中给出的 '_5x + 3 > 2x - 1_' 是干扰项,用于测试学生是否真正理解题意并列式。本题考查一元一次不等式组的建立,属于简单难度,符合七年级数学课程要求。","options":[]},{"id":2250,"content":"在数轴上,点A表示的数是-3,点B表示的数是5。若点C位于点A和点B的正中间,则点C表示的数是___。","type":"选择题","subject":"数学","grade":"七年级","stage":"初中","difficulty":"简单","answer":"D","explanation":"点A表示-3,点B表示5,两点之间的距离为5 - (-3) = 8。中点C将这段距离平均分为两部分,因此从点A向右移动4个单位即可到达中点。计算得:-3 + 4 = 1。因此,点C表示的数是1,正确答案是D。","options":[{"id":"A","content":"-1"},{"id":"B","content":"1"},{"id":"C","content":"2"},{"id":"D","content":"1"}]},{"id":634,"content":"13道","type":"选择题","subject":"数学","grade":"初一","stage":"小学","difficulty":"简单","answer":"待完善","explanation":"解析待完善","options":[]},{"id":378,"content":"某学生在平面直角坐标系中描出点 A(3, 4) 和点 B(-2, 1),他想知道线段 AB 的长度。根据两点间距离公式,线段 AB 的长度最接近下列哪个值?","type":"选择题","subject":"数学","grade":"初一","stage":"初中","difficulty":"简单","answer":"A","explanation":"根据平面直角坐标系中两点间距离公式:若两点坐标分别为 (x₁, y₁) 和 (x₂, y₂),则距离 d = √[(x₂ - x₁)² + (y₂ - y₁)²]。将点 A(3, 4) 和点 B(-2, 1) 代入公式:d = √[(-2 - 3)² + (1 - 4)²] = √[(-5)² + (-3)²] = √[25 + 9] = √34。计算 √34 的近似值约为 5.83,四舍五入后最接近 5.8。因此正确答案是 A。","options":[{"id":"A","content":"5.8"},{"id":"B","content":"6.2"},{"id":"C","content":"5.0"},{"id":"D","content":"4.5"}]}]