what is the equation of the trend line in the scatter plot?

Explanation:

Step1: Find two points on the trend - line

We can choose the two yellow points. Let the first point be $(4,0)$ and the second point be $(8,9)$.

Step2: Calculate the slope $m$

The slope formula is $m=\frac{y_2 - y_1}{x_2 - x_1}$. Substituting $x_1 = 4,y_1 = 0,x_2 = 8,y_2 = 9$ into the formula, we get $m=\frac{9 - 0}{8 - 4}=\frac{9}{4}=2.25$.

Step3: Use the point - slope form to find the y - intercept $b$

The point - slope form is $y - y_1=m(x - x_1)$. Using the point $(4,0)$ and $m = 2.25$, we have $y-0 = 2.25(x - 4)$. Expanding gives $y=2.25x-9$. In slope - intercept form $y = mx + b$, the y - intercept $b=-9$.

Answer:

$y = 2.25x-9$