中二數學功課

1.
y-1=4x-1/2 〔x〕
2(y-1) = 2*4x-1
2y-2=8x-1
2y-2+1=8x
2y-1 = 8x
x = (2y-1)/8

2.
Da+Eb=Ab 〔b〕
Da = Ab-Eb
Da = b(A-E)
b = (Da)/(A-E)

3.
B=2t/t-2 〔t〕
B=2t/(t-2)
B(t-2) = 2t
Bt-2B = 2t
Bt-2t = 2B
t(B-2) = 2B
t = (2b)/(B-2)

4.
x=a+kb/1+k 〔k〕
x = (a+kb)/(1+k)
x(1+k) = a+kb
x+kx = a+kb
kx-kb = a-x
k(x-b) = a-x
k = (a-x)/(x-b)

5.
1/abc+1/b=1/c 〔a〕
1/(abc)+1/b = 1/c
1+ac = ab
1 = ab-ac
1 = a(b-c)
a = 1/(b-c)