Finding x such that F(x) = 0.  Choose [a,b] such that F(a) and F(b) have opposite sign.
With "test" you find 10 values of F from a to b.

f(x) = a10*x^10+a9*x^9+a8*x^8+a7*x^7+a6*x^6+a5*x^5+a4*x^4 + a3*x^3 + a2*x^2 + a1*x + a0
a10 a9 a8 a7 a6
a5 a4 a3 a2 a1 a0

  a = b =  


examples