You have three equations:

$18\mathrm{.}200x-5\mathrm{.}0000Y+17\mathrm{.}000Z=5\mathrm{.}0000$

$12\mathrm{.}000x+21\mathrm{.}000Z=10\mathrm{.}000$

$3\mathrm{.}0000Y+8\mathrm{.}0000Z=15\mathrm{.}000$

Find the values of $x,Y,$ and $Z.$