Final answer:
To determine the equation(s) of the tangent line(s) at x=4, one would typically calculate the derivative (representing the slope at that point) of the original function and use the point-slope form to find the tangent line. Unfortunately, the initial equation appears to have a typo, and without the correct function form, an exact answer cannot be calculated.
Step-by-step explanation:
To find the equation(s) of the tangent line(s) to the graph of the given equation at x=4, we first need to identify the original function. However, there seems to be a typo in the initial equation provided. Assuming the correct equation resembles a quadratic or polynomial where we could take a derivative, the process to find the tangent line involves calculating the derivative of the function to find the slope of the tangent line at x=4, then using the point-slope form of a line to write the equation of the tangent.
Since specific details on the function in question are missing, we cannot calculate an exact answer. However, if we had a function f(x), we would compute f'(4) to get the slope, and if we know f(4) to find the y-coordinate of the point of tangency, we could write the equation of the tangent line as y - f(4) = f'(4)(x - 4).
For lines that are already in slope-intercept form, such as Y2 and Y3 mentioned, no calculation is necessary as these are already expressions for lines and share the same slope as the line of best fit described by the equation y = -173.5 + 4.83x.