Find the slope of the line. -7 , - 1/7, 7, 7/1

When only separate discreet points are graphed it is called?

Tim's phone service charges $26.39 plus an additional $0.21 for each text message sent per month. if tim's phone bill was $31.64, which equation could be used to find how many text messages, x, tim sent last month?

Let f(x) = 5/x and g(x)=2x2+5x. what two numbers are not in the domain of f o g