In every triangle, the sum of two sides must exceed the third one. So, we have three inequalities:
[tex] 2.7 + 4 > x \iff x < 6.7 [/tex]
[tex] 2.7+x > 4 \iff x > 1.3 [/tex]
[tex] 4+x > 2.7 \iff x > -1.3 [/tex]
So, x has to be less than 6.7, and more than 1.3 (since this request overrules the other one, because it's more restrictive)
