Enter your X values in one column and Y values in another column
Select the data range
Go to the Insert tab
Click Scatter chart
Choose a scatter plot
Click a data point in the chart
Right-click and select Add Trendline
Choose Linear trendline
Check Display Equation on chart
Check Display R-squared value on chart
Use the equation to predict Y values
Or use the SLOPE function to get the slope
Or use the INTERCEPT function to get the intercept
Or use the LINEST function for full regression output