Prove Lemma 2.

This is what i have so far but I want to to show that a + e > 0 implies either a = 0 or a > 0. For instance, -3 + 5 > 0 but -3 < 0. Since e > 0. for a + e < 0 to be true, a < -e would have to be true (why?). 

Prove Lemma 2.3.10 (2)Let a ERPart 1 a &gt; 0 if and only if a &gt; -8 for all = &gt; 0Suppose a 2 0Let z &gt;0Since a &gt; 0 and = &gt; 0 then a + 8 &gt; 0Then a &gt; -EPart 2 Suppose a &gt; -8 and = &gt; 0)Because &amp; &gt; 0 a can be equal to OSo a 20