Is this a function. ?

What is the answer to |-2x-5|-|-4+8| and x=7

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.

Add the fractions, and simply the result to lowest terms. 2/3 + 2/7= ?