> seconddegree:= proc(a,b,c)

if a=0 then if b=0 and c=0 then print ('infinite solutions')

elif b=0 and c<>0 then print ('impossible')

elif b<>0 and c<>0 then print (' one solution',x=-(c)/(b))fi;

delta:=b^(2)-4 *a*c;

elif if delta=0 then print('double solution',x=-b/(2 a))

elif delta >0 then print ('exist two solutions',x1=((-b+sqrt(delta)))/(2 a),x2=((-b-sqrt(delta)))/(2 a))

elif delta <0 then print ('exist two conjugate imaginary solutions', x1=((-b+I*sqrt(-delta)))/(2 a),x1=((-b-I*sqrt(-delta)))/(2 a))

fi;fi;end proc; ;

Error, invalid 'elif' clause