1. The problem is to use the Gauss Elimination method to solve the system of linear equations: $$a x + b y + c z = j$$ $$d x + e y + f z = k$$ $$g x + h y + i z = l$$ 2. Start by considering the first two equations to eliminate $x$ and express $y$ and $z$. 3. From the first equation, express $x$ as: $$x = \frac{j - b y - c z}{a}$$ 4. Substitute this expression for $x$ into the second equation: $$d \left(\frac{j - b y - c z}{a}\right) + e y + f z = k$$ Multiply both sides by $a$ to clear the denominator: $$d(j - b y - c z) + a e y + a f z = a k$$ Which expands to: $$d j - d b y - d c z + a e y + a f z = a k$$ Group terms with $y$ and $z$: $$(- d b + a e) y + (- d c + a f) z = a k - d j$$ 5. Solve for $y$: $$y = \frac{a k - d j - z(- d c + a f)}{- d b + a e} = \frac{d j - a k + z(c d - a f)}{b d - a e}$$ 6. The problem states this as: $$y = \frac{(d j - a k) - z(c d - a f)}{b d - a e}$$ 7. Finally, substitute $y$ and $z$ back into the first equation to find $x$: $$x = \frac{j - b y - c z}{a}$$ 8. Thus, the solution expressions are: $$z = z$$ $$y = \frac{(d j - a k) - z (c d - a f)}{b d - a e}$$ $$x = \frac{j - b y - c z}{a}$$ These are the formulas derived from Gauss Elimination method to express $x$ and $y$ in terms of $z$ and constants.