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怎么解这个方程组?420/a+80/b=11,240/a+140/b=11代入ab不行啊,急
题目详情
怎么解这个方程组?
420/a+80/b=11,240/a+140/b=11
代入ab不行啊,急
420/a+80/b=11,240/a+140/b=11
代入ab不行啊,急
▼优质解答
答案和解析
420/a + 80/b = 11……(1)
240/a + 140/b = 11……(2)
(1)*7:
2940/a + 560/b = 77……(3)
(2)*4:
960/a + 560/b = 44……(4)
(3)-(4):
1980/a = 33
a = 60
代入,得:b = 20
240/a + 140/b = 11……(2)
(1)*7:
2940/a + 560/b = 77……(3)
(2)*4:
960/a + 560/b = 44……(4)
(3)-(4):
1980/a = 33
a = 60
代入,得:b = 20
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