Can someone explain to me how to do this please

Can somebody me out with this question

1-for what value of x is line a parallel to line b 2-for what value of x is line a parallel to line b

State whether weight is a function of height for the six students and explain. a. yes, height is a function of weight because two students weigh 165 pounds but have different heights. b. no, height is not a function of weight because two students weigh 165 pounds but have different heights. c. yes, weight is a function of height because for each value of height there is one corresponding value of weight. d. no, weight is not a function of height because there is not enough data to determine a function.