1. The problem is to determine the equation of a trendline given a set of data points. 2. A trendline is typically a linear equation of the form $$y = mx + b$$ where $m$ is the slope and $b$ is the y-intercept. 3. To find the slope $m$, use the formula $$m = \frac{\sum (x_i - \bar{x})(y_i - \bar{y})}{\sum (x_i - \bar{x})^2}$$ where $\bar{x}$ and $\bar{y}$ are the means of the $x$ and $y$ values respectively. 4. Calculate the means: $$\bar{x} = \frac{1}{n} \sum x_i, \quad \bar{y} = \frac{1}{n} \sum y_i$$. 5. Compute the sums needed for $m$ using the data points. 6. Once $m$ is found, calculate the intercept $b$ using $$b = \bar{y} - m \bar{x}$$. 7. Write the final trendline equation as $$y = mx + b$$. 8. This equation can be used to predict $y$ values for given $x$ values along the trend.