中一數學`

希望你冇打錯題目

2- (t/4) = 2t - (3/5) +t
2- (t/4) = 3t - (3/5)
(2- (t/4))*20 = (3t - (3/5))*20
40-5t = 60t - 12
60t + 5t = 40+12
65t = 52
t= 52/65

t= 4/5

--------------------------------------------------
u-(1/2) - u+(1/8) = u/4
(1/2)+(1/8) = u/4
(1*4/2*4)+(1/8) = u/4
(4/8)+(1/8) = u/4
5/8 = u/4
(5/8)*4 = (u/4)*4

u = 5/2

2009-10-08 13:56:11 補充：
(2-t) /4 = (2t -3)/(5+t) , t=?
(u-1)/ 2 - (u+1)/8 = u/4 , u=?
希望你下次打埋括號=)
(2-t) /4 = (2t -3)/(5+t)
(2-t)(5+t) = 4(2t -3)
t^2 + 11t - 22 = 0

t=(-11+ sqroot(11^2 - 4(1)(-22)))/2(1)
OR
t=(-11- sqroot(11^2 - 4(1)(-22)))/2(1)

t=(-11+ sqroot(11*19))/2
OR
t=(-11- sqroot(11*19))/2

2009-10-08 13:56:39 補充：
(u-1)/ 2 - (u+1)/8 = u/4
(u-1)/ 2*8 - (u+1)/8*8 = u/4*8
4(u-1) - (u+1) = 2u
4u-4-u-1=2u
u=5

2-t /4 = 2t -3/5 +t
(2-t /4 )x20= (2t -3/5 +t)x20
40-5t=40t-12+20t
40-5t=60t-12
52=65t
t=52/65

u-1/ 2 - u+1/8 = u/4
(u-1/ 2 - u+1/8)x16 = (u/4)x16
16u-8-16u+2=4u
-6=4u
u=-6/4
u=-3/2

2009-10-07 23:43:38 補充：
第1題
2-t /4 = 2t -3/5 +t
(2-t /4 )x20= (2t -3/5 +t)x20
40-5t=40t-12+20t
40-5t=60t-12
52=65t
t=52/65
t=4/5

可以:2-t /4 = 2t -3/5
40-5t=40t-12
-45t=-52
t=52/45

u-1/ 2 - u+1/8 = u/4
8u-4-8u+1=2u
-2u=3
u=- 3/2