Find sin2x, cos2x, and tan2x if sinx=-15/17 and x terminates in quadrant III

1. what is the measure of ∠abc? what is the measure of ∠abd?

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?

Credit card a offers an introductory apr of 3.4% for the first three months and standard apr of 15.7% thereafter,