Mathematics

Problem

For real numbers

x

and

y

, if

x^2 + xy - y^2 + 2x - y + 1 = 0

, then : (a)

y

can not be between 0 and

\frac{8}{5}

(b)

y

can not be between

-\frac{8}{5}

and

\frac{8}{5}

(c)

y

can not be between

-\frac{8}{5}

and 0 (d)

y

can not be between

-\frac{16}{5}

and 0