Identify the slope and y-intercept of the equation.: $3 x+6 y=-18$

Step 1 ：The given equation is not in the slope-intercept form. The slope-intercept form of a linear equation is \(y = mx + c\), where \(m\) is the slope and \(c\) is the y-intercept. So, first, we need to rearrange the given equation into the slope-intercept form.

Step 2 ：Rearrange the equation \(3x + 6y = -18\) to the form \(y = mx + c\).

Step 3 ：By doing so, we get the equation \(y = -\frac{1}{2}x - 3\).

Step 4 ：The equation is now in the form \(y = mx + c\). The coefficient of \(x\) is the slope and the constant term is the y-intercept.

Step 5 ：So, the slope is \(-\frac{1}{2}\) and the y-intercept is \(-3\).

Step 6 ：Final Answer: The slope of the equation is \(\boxed{-\frac{1}{2}}\) and the y-intercept is \(\boxed{-3}\).