1. **State the problem:** Solve the system of linear equations:
$$4x + 2y = -16$$
$$5x + 9y = -85$$
2. **Formula and method:** We will use the substitution or elimination method. Here, elimination is convenient.
3. **Eliminate one variable:** Multiply the first equation by 9 and the second by 2 to align coefficients of $y$:
$$9(4x + 2y) = 9(-16) \Rightarrow 36x + 18y = -144$$
$$2(5x + 9y) = 2(-85) \Rightarrow 10x + 18y = -170$$
4. **Subtract the second from the first to eliminate $y$:**
$$ (36x + 18y) - (10x + 18y) = -144 - (-170) $$
$$ \Rightarrow (36x - 10x) + (18y - 18y) = -144 + 170 $$
$$ \Rightarrow 26x + \cancel{0} = 26 $$
5. **Solve for $x$:**
$$ 26x = 26 $$
$$ \Rightarrow x = \frac{26}{26} $$
$$ \Rightarrow x = 1 $$
6. **Substitute $x=1$ into the first equation to find $y$:**
$$4(1) + 2y = -16$$
$$4 + 2y = -16$$
$$2y = -16 - 4$$
$$2y = -20$$
$$y = \frac{-20}{2}$$
$$y = -10$$
7. **Final answer:**
$$\boxed{x=1, y=-10}$$
This means the solution to the system is the point $(1, -10)$ where both lines intersect.
Linear System Cfaea1
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