The slope of the line in question is the same as the slope of the line parallel to it. Using y = mx + b, where m is the slope, we find the slope of our line is -3.
Using the pt-slope form, y - y1 = m( x - x1), we get y - (-1) = -3( x - 2) or y + 1 = -3x + 6. Which leads us to y = -3x + 5. QED
