3a2+5a−7; 6a2−7a+13. x+2y−3z; −3x+y+2z; 2x−3y+z. 3x+2y−z; −x+3y+2z; 2x−y+3z. −3a+2b+c; a−3b+2c; 2a+3b−c. −a+3b+4c; 3a−b+2c; 2a+2b−2c. 4a2+3a+5; −2a2+3a−8; a2−a+1. 5ab+6bc−7ac; 3ab−9bc+4ac; 3bc+6ac. x3+x2+x; 2x3+3x2−2x; 3x3−4x2+x. 3y2−x2−3xy; 5x2+6xy−7y2; x2+2y2. 2a2−2ab+3b2; 4b2+5ab−2a2; a2−3ab−9b2. a3−a2+a−1; a2−2a+2; 3a3+7a+1. 2m3−m2−m; 4m3+8m2−7; −3m3+m+9. x3−3x+6y; x2+2x−5y; x3−3x2+5x. 6x3−5x+1; x3+3x+4; 7x2+2x−3. a 3 + 3 a 2 b − 3 a b 2 ; − 3 a