Final answer:
The best-fit line on a graph represents the equation y = mx + b, showing the trend of data by minimizing the sum of the squares of the residuals and passing through the mean of the x and y values.
Step-by-step explanation:
The line on a best-fit line graph represents the equation y = mx + b, where 'm' is the slope and 'b' is the y-intercept. The slope (m) indicates how the dependent variable (y) changes for each unit increase in the independent variable (x), and the y-intercept (b) represents the value of y when x is zero.
The best-fit line is the line that minimizes the sum of the squares of the vertical distances (residuals) between the data points and the line itself, effectively showing the trend of the data. The best-fit line always passes through the mean of the x values () and the mean of the y values (), which is the point (, ) on the graph.