Question

solve each system of equations by elimination. 9. \

$$\begin{cases} x + y = -5 \\\\ x - y = 9 \\end{cases}$$

10.

Explanation:

Step1: Add the two equations

$$(x + y) + (x - y) = -5 + 9$$
$$2x = 4$$

Step2: Solve for $x$

$$x = \frac{4}{2} = 2$$

Step3: Substitute $x=2$ into first equation

$$2 + y = -5$$

Step4: Solve for $y$

$$y = -5 - 2 = -7$$

Answer:

$x=2$, $y=-7$