(i) x2+y2+z2−xy+x+yz by x+y−z (ii) x2+4y2+z2+2xy+xz−2yz by x−2

1.	(i) x2+y2+z2−xy+x+yz by x+y−z (ii) x2+4y2+z2+2xy+xz−2yz by x−2y−z (iii) x2+4y2+2xy−3x+6y+9 by x−2y+3 (iv) 9x2+25y2+15xy+2x−20y+16 by 3x−5y+4
Answer» (i) $x^{2} + y^{2} + z^{2} - x y + x + y z by x + y - z$ (ii) $x^{2} + 4 y^{2} + z^{2} + 2 x y + x z - 2 y z by x - 2 y - z$ (iii) $x^{2} + 4 y^{2} + 2 x y - 3 x + 6 y + 9 by x - 2 y + 3$ (iv) $9 x^{2} + 25 y^{2} + 15 x y + 2 x - 20 y + 16 by 3 x - 5 y + 4$

(i) x2+y2+z2−xy+x+yz by x+y−z (ii) x2+4y2+z2+2xy+xz−2yz by x−2y−z (iii) x2+4y2+2xy−3x+6y+9 by x−2y+3 (iv) 9x2+25y2+15xy+2x−20y+16 by 3x−5y+4

Answer»

(i) $x^{2} + y^{2} + z^{2} - x y + x + y z by x + y - z$

(ii) $x^{2} + 4 y^{2} + z^{2} + 2 x y + x z - 2 y z by x - 2 y - z$

(iii) $x^{2} + 4 y^{2} + 2 x y - 3 x + 6 y + 9 by x - 2 y + 3$

(iv) $9 x^{2} + 25 y^{2} + 15 x y + 2 x - 20 y + 16 by 3 x - 5 y + 4$