F.2 MATHS......

1a)M =√ab [a]
M2 = ab
M2/b = a
a = M2/b

b)如果M = 9和b = 3,
a = M2/b
a = (9)2/3
a = 81/3
a = 27

2.如果a = -10, t = 2和h = 40
h = ut+ (1/2)at2
40 = u(2)+(1/2)(-10)(2)2
40 = 2u﹣20
60 = 2u
u = 30

3.x = 2﹣1/t / 2+ l/t [x]
你有打錯題目，x已經是主項...

4)180 = 200(1﹣r/100)
180/200 = 1﹣r/100
r/100 = 1﹣(180/200)
r/100 = 1﹣(9/10)
r/100 = 1/10
r = 100/10
r = 10

2007-12-21 19:02:09 補充：
3.x = 2﹣(1/t/2)+ l/t [t]x = 2﹣(1/2t)+ l/tx = 4t/2t﹣1/2t+ 2l/2tx = (4t﹣1+ 2l)/2t2tx = 4t﹣1+ 2l2tx﹣4t = 2l﹣1t(2x﹣4) = 2l﹣1t = (2l﹣1)/(2x﹣4)

1a.M=√ab (a)
　M^2 = ab
　M^2 ÷ b = a
　
1b.如果M=9和b=3,求a的值
　9 x 9 ÷ 3 = a
　a = 27

2.h=ut+1/2at^2
如果a=-10,t=2和h=40,求u的值
　40 = u x 2 + 0.5 x (-10) x (2x2)
　40 = 2u + (-20)
　40 = 2u - 20
　40 + 20 = 2u
　60 ÷ 2 = u
　u = 30

3.x=2- 1/t / 2+ l/t (x)
　(x) ??

4.180=200(1-r/100)
　180 ÷ 200 = 1 - r / 100
　r / 100 = 1 - 0.9
　r = 0.1 x 100
　r = 10

2007-12-21 19:26:32 補充：
3.x=2- 1/t / 2 l/t (t) 　x = 2 - 1/t ÷ 2 1/t　x = 2 - 1/t x 1/2 1/t　tx = 2t - t/t x t/2 t/t　tx = 2t - 1 x t/2 1　tx ÷ t/2 - 2t = 1　2tx ÷ t - 4t = 2　t (2x ÷ 1 - 4) = 2　t (2x - 4) = 2　t = 2 ÷ (2x - 4)