1) 7/x - 3/x(x+4)
2) 5/3x - 1/y over 7x - 4/y
1) THE ANSWER IS 7X+25/X(X+4)
2) 5Y-3X / 21 XY - 12X
I KNOW THE ANSWER BUT HOW DO U DO IT?
MATH HELP, MUCH APPRECIATED?
2016-06-14 3:47 am
回答 (1)
2016-06-14 3:57 am
(1)
[7 / x] - [3 / x(x + 4)]
= [7(x + 4) / x(x + 4)] - [3/x(x + 4)]
= [7(x + 4) - 3] / x(x + 4)
= [7x + 28 - 3] / x(x + 4)
= (7x + 25) / x(x + 4)
(2)
[(5 / 3x) - (1 / y)] / [(7 / x) - (4 / y)]
= [(5y / 3xy) - (3x / 3xy)] / [(7y / xy) - (4x / xy)]
= [(5y - 3x) / 3xy] / [(7y - 4x) / xy]
= [(5y - 3x) / 3xy] × [xy / (7y - 4x)]
= [(5y - 3x) / 3] × [1 / (7xy - 4x)]
= (5y - 3x) / 3(7xy - 4x)
= (5y - 3x) / (21xy - 12x)
[7 / x] - [3 / x(x + 4)]
= [7(x + 4) / x(x + 4)] - [3/x(x + 4)]
= [7(x + 4) - 3] / x(x + 4)
= [7x + 28 - 3] / x(x + 4)
= (7x + 25) / x(x + 4)
(2)
[(5 / 3x) - (1 / y)] / [(7 / x) - (4 / y)]
= [(5y / 3xy) - (3x / 3xy)] / [(7y / xy) - (4x / xy)]
= [(5y - 3x) / 3xy] / [(7y - 4x) / xy]
= [(5y - 3x) / 3xy] × [xy / (7y - 4x)]
= [(5y - 3x) / 3] × [1 / (7xy - 4x)]
= (5y - 3x) / 3(7xy - 4x)
= (5y - 3x) / (21xy - 12x)
收錄日期: 2021-04-18 15:15:24
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160613194724AAOxnls