Hi

2.

Let a rational zero of F, p and q having no common factor

Multiplying by

p divides 0 therefore p divides

And p divides each item of the sum therefore p divides

p and q having no common factor p divides 16

p = +/- 1, 2, 4, 8, 16

Same method for q leads to q=1

3. All the parallels to 2x+3y=6 have an equation like 2x+3y=c

The one passing through the point (1,-1) is therefore 2x+3y=2.1+3.(-1)=-1