I think of a number, square it, then subtract the original number. The result is 30. What could the number be

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?

How do you write y-10=2 (x-8) in standard form

Aline passes through the point (–7, 5) and has a slope of 1/2 which is another point that the line passes through?