《2025年暑假衔接课堂七年级数学浙教版》

3. 某公园举行暑期特优读书游园活动,成人票和儿童票均有较大的折扣,张凯、李利都随他们的家人参加了本次活动,王斌也想去,就打听张凯、李利买门票花了多少钱. 张凯说他家去了3个大人和4个小孩,共花了77元钱;李利说他家去了2个大人和1个小孩,共花了38元钱. 王斌家计划去2个大人和2个小孩,请你帮他算一下,需准备46元钱买门票.

答案： 3. 46

4. 解方程组:
(1) $\begin{cases}3x - 4(x - 2y) = 5, \\x - 2y = 1; \end{cases}$$\left\{\begin{array}{l} x=3,\\ y=1.\end{array}\right.$
(2) $\begin{cases}2(x + 1) + y - 2 = 7, \\2(x + 1) - 3(y - 2) = -1; \end{cases}$$\left\{\begin{array}{l} x=\frac {3}{2},\\ y=4.\end{array}\right.$
(3) $\begin{cases}\dfrac{x + y}{2} + \dfrac{x - y}{3} = 6, \\4(x + y) - 5(x - y) = 2; \end{cases}$$\left\{\begin{array}{l} x=7,\\ y=1.\end{array}\right.$
(4) $\begin{cases}\dfrac{4}{x} + \dfrac{5}{y} = 13, \\\dfrac{4}{x} - \dfrac{5}{y} = 3; \end{cases}$$\left\{\begin{array}{l} x=\frac {1}{2},\\ y=1.\end{array}\right.$
(5) $\begin{cases}9(x + y) + (x - y) = 25, \\2(x + y) - (x - y) = 8; \end{cases}$$\left\{\begin{array}{l} x=\frac {1}{2},\\ y=\frac {5}{2}.\end{array}\right.$
(6) $\begin{cases}\dfrac{x}{5} + \dfrac{y}{7} = 12, \\\dfrac{y}{5} + \dfrac{x}{7} = 12. \end{cases}$$\left\{\begin{array}{l} x=35,\\ y=35.\end{array}\right.$

答案： 4.
(1)$\left\{\begin{array}{l} x=3,\\ y=1.\end{array}\right. $
(2)$\left\{\begin{array}{l} x=\frac {3}{2},\\ y=4.\end{array}\right. $
(3)$\left\{\begin{array}{l} x=7,\\ y=1.\end{array}\right. $
(4)$\left\{\begin{array}{l} x=\frac {1}{2},\\ y=1.\end{array}\right. $
(5)$\left\{\begin{array}{l} x=\frac {1}{2},\\ y=\frac {5}{2}.\end{array}\right. $
(6)$\left\{\begin{array}{l} x=35,\\ y=35.\end{array}\right. $