maths(20pts)!!(MC)

🎓 學業台小學及中學教育

用戶112355

2007-03-20 5:48 am

1.find the coefficient of x in the expansion of (3x-1)(4x+7)??
A.25
B.21
C.17
D.13
Please show the answer and the steps clearly!THX!

回答 (3)

Eric

2007-03-20 5:59 am

C.........

參考: me

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rainbow

2007-03-20 5:53 am

(3x-1)(4x+7)= 12x^2 + 21x - 4x - 7
= 12x^2 + 17x -7

so the coefficient of x is 17

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2007-03-20 5:51 am

(3x-1)(4x+7)=12x^2+17x-7
Therefore, C is the answer.

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