[tex] {(a + b)}^{3} = {a}^{3} + 3 {a}^{2} b + 3a {b}^{2} + {b}^{3} [/tex]

[tex]125 {a}^{3} + 675 {a}^{2} + 1215a + 729 = {(5a + 9)}^{3} [/tex]