Program P0001;
var
q: string;
a, b, rez: integer;
ravno: real;
procedure opredel(s: string; VAR a, b, r: integer);
var
i, q: integer;
aa: string;
begin
if pos('x', s) = 1 then
aa := '1'
else
begin
q := 0;
for i := 1 to pos('x', s) do
inc(q);
aa := copy(s, 1, q - 1);
end;
val(aa, a, i);
if a = 0 then
a := -1;
q := 0;
for i := pos('x', s) + 1 to pos('=', s) do
inc(q);
aa := copy(s, pos('x', s) + 1, q - 1);
val(aa, b, i);
q := 0;
for i := pos('=', s) to length(s) do
inc(q);
aa := copy(s, pos('=', s) + 1, q);
val(aa, r, i);
end;
begin
q := '7x+4=-3';
opredel(q, a, b, rez);
ravno := (rez + (-b)) / a;
writeln(ravno:0:5);
readln;
end.