APowerOfACandidateWithASymbolicFactorMayBeLeftIn​(AngouriMath.​Entity,​AngouriMath.​Entity,​AngouriMath.​Entity.​Variable)

Whether candidate is a factor free of x with a
symbol in it times a function of x, and what it leaves of
x in integrandInU may be a constant times its power
from -2 to 2: the quotient by one of those powers does not vary with x,
read off two points, or cannot be read there. That is what
WithTheCandidatesPowerLeftInX(AngouriMath.Entity,AngouriMath.Entity,AngouriMath.Entity.Variable,AngouriMath.Entity.Variable) takes from the simplified quotient, where the
factor stands on both sides of the bar and its cancelling is the condition that it is not
zero, under which the candidate varies at all. Never beside a linear candidate, which that
rewriting does not read.