(2) When n= 100:

y=3x 100+ 1

=30 1

That is to say, to build 100 squares, it takes 30 1 matchstick;

When y= 100:

100=3n+ 1

∴3n=99

n=33

That is, 100 matches can make 33 squares.

I am glad to solve the above problems for you, and I hope it will help your study! ≤、≥ ∠