Answer:
D. \(y=-3x-21\)
Step-by-step explanation:
We have been given that every time x increases by 1,y decreases by 3. This means that slope of our given line is negative 3.
We will use slope-intercept form of equation to find the required function.
\(y=mx+b\), where,
m = Slope of line,
b= The y-intercept.
Upon substituting \(m=-3\) and \(x=-6\) and \(y=-3\) in slope-intercept form of equation, we will get,
\(-3=-3\times -6+b\)
\(-3=18+b\)
\(-3-18=18-18+b\)
\(-21=b\)
Upon substituting \(m=-3\) and \(b=-21\) in slope-intercept form of equation, we will get our required equation as:
\(y=-3x-21\)
Therefore, option D is the correct choice.
