What does 1a demonstrate about expressions?

Hm, 

I think it means 1 multiplied by a random number, or variable in this case.

After all, the numerals in (1a–b) and the numerals in (3a–b) are not plausibly homonyms. ... Co-referringexpressions are often not substitutable, so (5) does no more than further demonstrate the inadequacy of the naïve reference principle.

Idon’t understand sorry

You would need a laid out graph for this but could you provide a picture of just a graph? i can give stepssolve for y.subtract 4xdivide by -1 (opposites)graph slope intercept formcheck each point to see if it’s on the graph