Let sin a = 12/13 with 90º≤a≤180º and tan b = -4/3 with 270º≤b≤360º. find tan (a - b).

a) -63/65
b)56/33
c)-16/63
d)65/56

a function could be identified in 3 ways either on a chart,graph, or ordered pairs. first a function is that each point has its own. the rule is that there can be many x's to one y but there can not be 2 x's at different y's. so on a graph when you put a straight line through the y's there should be one dot only to be a function.

step-by-step explanation: