When solving simultaneous equations with a linear and quadratic equation, there will usually be two pairs of answers.

Learn how to form, manipulate and solve quadratic equations. Revise expansion of expressions and factorising and forming quadratics.

George Mackiw, The Linear Group SL (2, 3) as a Source of Examples, The Mathematical Gazette, Vol. 81, No. 490 (Mar., 1997), pp. 64-67 ...