The equation of a circle is x2 − 4x + y2 + 8y − 29 = 0. what are the center and radius of the circle?

Tom had a total of $220 and he spent $35 on a basketball ticket . what percent of his money did he have left?

Ineed in figuring out this problem.

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?