This looks like it could be a difference of squares (x^6-y^6), but 729 = 9^3, so we'll have to treat it as a difference of cubes.
(x^2)^3 - (9y^2)^3 = (x-9y)(x^4+9y^2+81y^4)
Factorise..x^6 -729 y^6
2 answers
actually, in thinking about it, 729 = 9^3 = 3^6 = 27^2. So,
x^6-729 = (x^3)^2 - (27y^3)^2
= (x^3-27y^3)(x^3+27y^3)
= (x-3y)(x^2+3xy+9y^2)(x+3y)(x^2-3xy+9y^2)
x^6-729 = (x^3)^2 - (27y^3)^2
= (x^3-27y^3)(x^3+27y^3)
= (x-3y)(x^2+3xy+9y^2)(x+3y)(x^2-3xy+9y^2)
1 answer