maths題

2006-11-28 3:54 am

數學測驗有題目18題,答岩一題有2分,答錯一題扣1分,如果答哂所有題目,拎到24分,,問答岩幾多題??
利用方程解應用題

回答 (3)

2006-11-28 3:59 am

✔ 最佳答案

let x be the number of questions that answer correctly
2x-1(18-x)=24
2x-18+x=24
3x=42
x=14
.`.the number of questions that answer correctly is 14

參考: meme

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2006-11-28 6:19 am

設答對了ｘ題，
2x-1(18-x)=24
2x-18+x=24
3x=42
x=14
.'.答對了１４題

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2006-11-28 4:01 am

2x-1(18-x)=24
2x-18+x=24
3x-18=24
3x=24+18
x=42/3
x=14
He answered 14 questions correctly.

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