Factorise the following:
(i) 10 x^{2}-18 x^{3}+14 x^{4}
(ii) 5 x^{2} y+10 x y z+15 x
(iii) p^{2} x^{2}+c^{2} x^{2}-a c^{2}- ap^{2}
(iv) 15(x+y)^{2}-5 x-5 y
(\mathbf{v})(\mathbf{a} \mathbf{x}+\mathbf{b} \mathbf{y})^{2}+(\mathbf{a} \mathbf{y}-\mathbf{b} \mathbf{x})^{2}
(v i) a x+b y+c x+b x+c y+a y
(vii) 49 x^{2}-70 x y+25 y^{2}
(viii) 4 a^{2}+12 a b+9 b^{2}
(ix) 49 p^{2}-36 q^{2}
(x) 100 x^{3}-25 x y^{2}
(xi) x^{2}-2 x y+y^{2}-z^{2}
(xii) x^{8}-y^{8}
(xiii) 12 x^{3}-14 x^{2}-10 x
(xiv) p^{2}-10 p+21
(xv) 2 x^{2}-x-6
(xvi) 6 x^{2}-5 x y-6 y^{2}
(xvii) x^{2}+2 x y-99 y^{2}