\[\begin{cases} x^2 + y^2 = 61 \\ x^2 - y^2 = 11 \end{cases}\]

\[\begin{align*} 1.\left\{\begin{array}{l} x_1 = \square\\ y_1 = \square \end{array}\right.\qquad\qquad\qquad\qquad\qquad\qquad 2.\left\{\begin{array}{l} x_2 = \square\\ y_2 = -\square \end{array}\right.\\\ 3.\left\{\begin{array}{l} x_3 = -\square\\ y_3 = \square \end{array}\right.\qquad\qquad\qquad\qquad\qquad 4.\left\{\begin{array}{l} x_4 = -\square\\ y_4 = -\square \end{array}\right. \end{align*}\]