Chapter R - Review of Basic Concepts - R.4 Factoring Polynomials - R.4 Exercises - Page 44: 103

$(10x+7y)(100x^{2}-70xy+49y^{2})$

$1000x^{3}=(10x)^{3},\qquad 343y^{3}=(7y)^{3}$ so we recognize this as a sum of cubes, $A^{3}+B^{3}=(A+B)(A^{2}-AB+B^{2})$ $...=(10x+7y)[(10x)^{2}-(10x)(7y)+(7y)^{2}]$ $=(10x+7y)(100x^{2}-70xy+49y^{2})$