Answer:
Sowwy :< I don't know
Step-by-step explanation:
Your answer would be 3 and 1/8
6 + (10 x 2) = 26 = (12+1)*2
The given function is that is a cubic polynomial

when arranged in descending order that is from highest degree to lowest degree

Since it is a three degree polynomial it has three roots.
According to rational root theorem , the possible roots of the above expression that is factors of
=
are 
As you can see from the graph all roots of this polynomial are real.
The smallest positive root is 0.954 and smallest negative root are -0.724.