begin
	comment square equation;
	
	real a, b, c;
	real d;
	real x1, x2;
	
	outstring(1,"coefficients a,b,c = ");
	inreal(0,a); inreal(0,b); inreal(0,c);
	
	d := b*b - 4.0*a*c;
	if d > 0.0 then
	begin
		x1 := (-b + sqrt(d) )/2.0/a;
		x2 := (-b - sqrt(d) )/2.0/a
	end;
	
	outstring(1,"solution = ");
	outreal(1,x1); outreal(1,x2);
	outstring(1,"\n")
	
end