三、解答题(共50分)
答案
11. (每小题5分,共20分)解下列二元一次方程组:
(1)$\begin{cases}x - y = 2,\\4x + 2y = - 1;\end{cases}$
(2)$\begin{cases}3m - 2n = 13,\\4m + 3n = 6;\end{cases}$
(3)$\begin{cases}5(x - 3y)-6 = 2x - 5,\\3(x + 6y)+10 = 9y + 19;\end{cases}$
(4)$\begin{cases}\frac{2(x - y)}{3}=\frac{x + y}{2}-1,\\6(x + y)=4(2x - y)+20.\end{cases}$
(1)$\begin{cases}x - y = 2,\\4x + 2y = - 1;\end{cases}$
(2)$\begin{cases}3m - 2n = 13,\\4m + 3n = 6;\end{cases}$
(3)$\begin{cases}5(x - 3y)-6 = 2x - 5,\\3(x + 6y)+10 = 9y + 19;\end{cases}$
(4)$\begin{cases}\frac{2(x - y)}{3}=\frac{x + y}{2}-1,\\6(x + y)=4(2x - y)+20.\end{cases}$
答案
12. (6分)某商场按定价销售某种商品时,每件可获利60元.若按定价的八折销售该商品5件与将定价降低40元销售该商品4件所获得的利润相等,则该商品每件的进价和定价分别是多少元?
答案
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