5y-y2-36
Reorder 5y and -y2.
-y2+5y-36
Factor -1 out of -y2.
-(y2)+5y-36
Factor -1 out of 5y.
-(y2)-(-5y)-36
Rewrite -36 as -1(36).
-(y2)-(-5y)-1(36)
Factor -1 out of -(y2)-(-5y).
-(y2-5y)-1(36)
Factor -1 out of -(y2-5y)-1(36).
-(y2-5y+36)
Factor 5y-y^2-36