Question

b. y=-x-6
x+3y=-18

Explanation:

Step1: Substitute $y=-x-6$ into second equation

$x + 3(-x - 6) = -18$

Step2: Expand and simplify the left side

$x - 3x - 18 = -18$

Step3: Combine like terms

$-2x - 18 = -18$

Step4: Isolate the $x$-term

$-2x = -18 + 18$
$-2x = 0$

Step5: Solve for $x$

$x = \frac{0}{-2} = 0$

Step6: Substitute $x=0$ into $y=-x-6$

$y = -0 - 6 = -6$

Answer:

$x=0$, $y=-6$