Which axiom would justify the following conclusion? if x + 4 = 12, then x = 8.

What is this inequality notation? t is less then or equal to 2

Tim's phone service charges $23.06 plus an additional $0.22 for each text message sent per month. if tim's phone bill was $28.56, which equation could be used to find how many text messages, x, tim sent last month?

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?