Elimination Method 99Cf7E
1. **State the problem:** Solve the system of equations using the elimination method:
$$4x + y = 9$$
$$x + \frac{1}{9}y = 4$$
2. **Goal:** Eliminate one variable by making the coefficients of either $x$ or $y$ the same in both equations.
3. Multiply the second equation by 9 to clear the fraction:
$$9 \times \left(x + \frac{1}{9}y\right) = 9 \times 4$$
$$9x + y = 36$$
4. Now the system is:
$$4x + y = 9$$
$$9x + y = 36$$
5. Subtract the first equation from the second to eliminate $y$:
$$(9x + y) - (4x + y) = 36 - 9$$
$$9x - 4x + y - y = 27$$
$$5x = 27$$
6. Solve for $x$:
$$x = \frac{27}{5} = 5.4$$
7. Substitute $x = 5.4$ into the first equation to find $y$:
$$4(5.4) + y = 9$$
$$21.6 + y = 9$$
$$y = 9 - 21.6 = -12.6$$
**Final answer:**
$$x = 5.4, \quad y = -12.6$$