Given the slope of the straight line k = 2, P1 (3,5), P2 (x2,7), P3 (- 1, Y3) are the three points on the straight line, find X2, Y3 Does anyone know

Given the slope of the straight line k = 2, P1 (3,5), P2 (x2,7), P3 (- 1, Y3) are the three points on the straight line, find X2, Y3 Does anyone know

Please think about it
General formula of linear equation y = KX + B
The three points are all on the straight line, which are substituted into the equation respectively
5=3k+b -------b=5-3k
7=kx2+b -------kx2=7-5+3k=2+3k -----k=2---- x2=4
y3=-1k+b -------y3=-1k+5-3k -----k=2---- y3=-3