Fixed point for the family of parabolas
Let P_m be the family of parabolas definited by the functions: f_m(x)=mx²+2(m-1)x+m-1, m≠0
a) Show that the vertices of the parabolas P_m associated functions fm is located on the line x + y = 0
b) Show that P_m parabolas pass through a fixed point.