Answers

2014-02-24T21:03:22+08:00
Ax + y = c
ax + by = 0

Multiply the first equation by -1.
-ax - y = -c
ax + by = 0
Equals:
  by = -c
 y = 
 \frac{-c}{b}

ax + b(  \frac{-c}{b} ) = 0
ax -c = 0
a =  \frac{c}{x}

c = 2ax + b2y
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