Please help me. Ive needed help on this for a long time

What is the solution to the system of equations? (–2, –8) (–1, –5) (0, –2) (2, 4)

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?

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?