Question

joaquin and serena are looking at the problem 3x+1>0 serena says that the inequality is always true because multiplying a number by three and then adding one to it makes the number greater than zero, is she right explain why or why not

Answer 1

Serena is wrong. She has completely ignored negative numbers.
With negative numbers, it is possible to have an answer that is less than zero.
For example, x=-2
3(-2)+1= -5
which is not > than 0.

Answer 2

Unfortunately, Serena is not correct. She has apparently lost sight of
most of the world of negative numbers.

In fact, if 'x' is ANY number less than negative 1/3, then 3x+1 is less than zero.

There are a huge load of numbers that qualify.