《2025年暑假作业新疆青少年出版社七年级数学人教版》

1.用指定的方法解下列方程组:
(1)(代入法)$\left\{\begin{array}{l} 2x+y= 4,\\ 3x-2y= 13;\end{array}\right. $
(2)(加减法)$\left\{\begin{array}{l} 4x+2y= 3,\\ 9x+3y-9= 0.\end{array}\right. $

答案：
(1)$\left\{\begin{array}{l} x=3,\\ y=-2\end{array}\right. $
(2)$\left\{\begin{array}{l} x=1.5,\\ y=-1.5\end{array}\right. $

2.用整体代入法解方程组:
(1)$\left\{\begin{array}{l} x+2y= 3\enclose{circle} {1},\\ 3x-4y= 4\enclose{circle} {2};\end{array}\right. $
(2)$\left\{\begin{array}{l} \frac {x+y}{2}+\frac {x-y}{3}= 6\enclose{circle} {1},\\ 4(x+y)-5(x-y)= 2\enclose{circle} {2}.\end{array}\right. $

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

3.解方程组$\left\{\begin{array}{l} 3x+2(x+y)= -1\enclose{circle} {1},\\ 3y-4(x+y)= 5\enclose{circle} {2}.\end{array}\right. $

答案： $\left\{\begin{array}{l} x=-3,\\ y=7\end{array}\right. $