Which of the relations given by the following sets of ordered pairs is not a function

Use set buikder notation to represent the following set: {, -2, -1, 0}

If 1/√5+1/√5+1=p+q√r , find the values of p, q and r

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?