/ 2 \ (a - 7)*\a + 7*a + 49/
(a - 1*7)*(a^2 + 7*a + 49)
3 -343 + a
-343 + a^3
/ ___\ / ___\ | 7 7*I*\/ 3 | | 7 7*I*\/ 3 | 1*(a - 7)*|a + - + ---------|*|a + - - ---------| \ 2 2 / \ 2 2 /
((1*(a - 7))*(a + (7/2 + 7*i*sqrt(3)/2)))*(a + (7/2 - 7*i*sqrt(3)/2))
(-7.0 + a)*(49.0 + a^2 + 7.0*a)