a1x+b1y=c1
A2x+b2y=c2
等于 a1*A2*x+b1*A2*y=c1*A2 1
a1*A2*x+a1*b2*y=c2*a1 2
等式1减去等式2.得到
y(b1*A2-a1*b2)=c1*A2 -c2*a1
等于y=(c1*A2 -c2*a1)/(b1*A2-a1*b2).
同理:
x=(c1*b2-c2*b1)/(a1*b2-A2*b1)
a1x+b1y=c1
A2x+b2y=c2
等于 a1*A2*x+b1*A2*y=c1*A2 1
a1*A2*x+a1*b2*y=c2*a1 2
等式1减去等式2.得到
y(b1*A2-a1*b2)=c1*A2 -c2*a1
等于y=(c1*A2 -c2*a1)/(b1*A2-a1*b2).
同理:
x=(c1*b2-c2*b1)/(a1*b2-A2*b1)