Answer:
D. 6
Step-by-step explanation:
The line of best fit represents the relation between two variables, usually indicated as x and y, where "x" is the independent variable and "y" is the dependent variable.
The general form of equation of the line of fit y = mx + b, where "m" represents the slope and b represents the y-intercept.
The given line of best fit of a scatter plot is y = 6x - 9
Now compare the given equation with the general and find the slope.
When we comparing, we get m = 6 which is the slope of the given equation.
Therefore, answer is D. 6