Answer
$x$ = $\frac{1}{2}$s -$\frac{3}{2}$t -$\frac{1}{4}$
Work Step by Step
-4$x$ + 2$y$ - 6$z$ = 1
4$x$ = 2$y$ - 6$z$ - 1
$x$ = $\frac{1}{2}$$y$ - $\frac{3}{2}$$z$ - $\frac{1}{4}$
Now add parameters for $y$ and $z$.
So, $y$ = $s$, and $z$ = $t$.
$x$ = $\frac{1}{2}$s -$\frac{3}{2}$t -$\frac{1}{4}$