just wondering how they got

using matrix, solve these linear equations:

$\displaystyle -x+y=4$

$\displaystyle 2x+5y=-2$

$\displaystyle

X = A^{-1}C

$

$\displaystyle X = (a, b, c, d) (x, y)$

$\displaystyle

X = (\frac{-1}{3}, \frac{1}{3}, \frac{2}{15}, \frac{1}{15})(4,-2)

$

$\displaystyle

X = (-2, \frac {2}{5})

$ <---how did they get this answer. Multiplying what exactly from above.

EDIT: its okay i figured it out :)