主項變換**急用!

1. x = a + ( n - 1 ) d [ 變換為 n ]
x = a + ( n - 1 ) d
x-a=( n - 1 ) d
n=[(x-a)/d]+1
2. 1/a - 1/b = 1/c [ 變換為 b ]
1/a - 1/b = 1/c
1/b=1/a - 1/c
1/b=(c-a)/ac
b=ac/(c-a)
3. A = P + Pnr over 100 [ 變換為 P ]
A = P + Pnr /100
A=P(1+ nr /100)
A=P(100+ nr) /100
P=100A/(100+ nr)
4. S = a - aR^n over 1 - R [ 變換為 a ]
S = a - aR^n /(1 - R)
S=a[1-R^n /(1 - R)]
S=a[(1-R-R^n) /(1 - R)]
a=S(1-R)/(1-R-R^n)

1)x = a + ( n - 1 ) d [ 變換為 n ]
x = a + ( n - 1 ) d
x - a = (n - 1) d
x - a/d = n - 1
( x - a/d ) - 1 = n
n = ( x - a/d ) - 1

2)1/a - 1/b = 1/c [ 變換為 b ]
1/a - 1/b = 1/c
a - b = c
- b = c -a
b = a - c

3)A = P + Pnr over 100 [ 變換為 P ]
A = P + Pnr over 100
100A = P + Pnr
100A = P (1 + nr)
100A over (1+nr) = P
P = 100A over (1+nr)

4)S = a - aR^n over 1 - R [ 變換為 a ]
S = a - aR^n over 1 - R
s( 1 - R ) = a ( 1 - R^n )
s - sR/( 1 - R^n ) = a
a = s - sR/( 1 - R^n )

1. x = a + ( n - 1 ) d
x = a + dn - d
dn = x - a + d
n = (x - a +d)/d

2. 1/a - 1/b = 1/c
b/a - 1 = b/c
b/a - b/c = 1
cb/ac - ab/ac = 1
(cb - ab)/ac = 1
cb - ab = ac
b(c-a) = c
b = ac/(c-a)

3. A = P + Pnr over 100
A = P + Pnr /100
A = P (1 + nr/100)
P = A/(1 + nr/100)

4. S = a - aR^n over 1 - R
S = a - aR^n / - R
S = a( 1 - R^n / -R)
a = S/( 1 - R^n / -R)