Use $m=\frac{y_2-y_1}{x_2-x_1}$ with your two chosen points.

After you know $m$, plug one point into $y=mx+b$ to solve for $b$.

In Desmos, enter the two points the line passes through:

• A=(20,50)
• B=(50,140)

Enter the line through $A$ and $B$:

y-50=((140-50)/(50-20))(x-20)

Simplify the line’s equation (or compare its slope and intercept) to identify which listed equation matches the Desmos line.

From the graph, the line of best fit passes through the grid intersection points $(20,50)$ and $(50,140)$.

Compute the slope:

Use $(20,50)$ to find $b$ in $y=mx+b$:

With $m=3$ and $b=-10$, the line’s equation is $y=3x-10$.