If the line y = x + 3-1 is rotated 15 ° counterclockwise around a point (1, 3) above it, the equation of the line is______ .

If the line y = x + 3-1 is rotated 15 ° counterclockwise around a point (1, 3) above it, the equation of the line is______ .

The slope of the straight line y = x + 3-1 is 1, so the inclination angle is 45 ° and the inclination angle of the rotated straight line is 60 ° and the slope is 3. So the equation of the straight line is Y-3 = 3 (x-1), that is, 3x-y = 0. So the answer is 3x-y = 0