Kramer's rule

eg:
3x + 7y = 12
12x - 11y = 2

x + y =
x + y =

x:    y:

explanation:

Kramer's rule

for:
     ax + by = c
     dx + ey = f

the following can be applied:

     x = (c * e - b * f ) / (a * e - b * d)
     y = (a * f - e * d) / (a * e - b * d)

This is known as Kramer's Rule.