Answer
a. Given any real number, you can find a real number so that the sum of the two is zero. In other words, every real number has an additive inverse. This statement is true.
b. There is a real number with the following property: No matter what real number is added to it, the sum of the two will be zero. In other words, there is one particular real number whose sum with any real number is zero.
This statement is false; no one number will work for all numbers. For instance, if x + 0 = 0, then x = 0, but in that case x + 1 = 1 = 0.
Work Step by Step
Recall that $\forall$ stands for "for all" and $\exists$ stands for "there exists."
