快快快!!!!問幾題數學題!!

38) x/a+x/b=c/d
xbd/abd+xad/abd=abc/abd
xd(a+b)/abd=abc/abd
xd(a+b)=abc
x=abc/d(a+b)

39) ax-b/x-d=e
x(a+b/d)=e
x=e/(a+b/d)

5) -xy+4x
x(-y+4)

have you learnt factorized?
If yes, the solution of the fifthe question is simply.............
-x(y - 4).................
you have known the answers of the first two questions.....
38. x = abc / ad + bd
39 . ..........the answer is not correct until now............
maybe I can tell you later

38.
x/a+x/b=c/d
(ax+bx)/ab=c/d
ax+bx=abc/d
x(a+b)=abc/d
x=(abc/d)/(a+b)
x=abc/(ad+db)


未寫完問題嗎？

38. x/a+x/b=c/d
(a+b)x/ab=c/d
x=abc/d(a+b)
=abc/ad+ab

39.ax-b/x-d=e
ax-b=ex-de
(a-e)x=b-de
x=b-de/a-e

2006-11-13 19:49:44 補充：
38. is wrong x=abc/ad+bd

2006-11-13 19:50:00 補充：
38. is wrong x=abc/ad+bd