13. GRE Lesson: Greatest Common Divisor,Greatest Common Divisor. Euclidean algorithm,Factorise by taking out the common factors : xy(3x^(2) - 2y^(2)) - yz(2y^(2) - 3x^(2)) + zx(15x^,Greatest Common Divisor (w/ 13 Step-by-Step Examples!),Common Factors Calculator