2 7*x - 1
7*x^2 - 1*1
/ ___\ / ___\ | \/ 7 | | \/ 7 | 1*|x + -----|*|x - -----| \ 7 / \ 7 /
(1*(x + sqrt(7)/7))*(x - sqrt(7)/7)
-1.0 + 7.0*x^2