如题所述
ä¸
1ã c
2ã c
3ã c
äº
4ã(9+16) t =400
5ã27ï¼3
6ã18.8
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7ã60xï¼ 80xï¼ 140xï¼ 60x+80x=700
(60 + 80) x = 700
x = 5