Hello! which of the following are true statements about the expression -9+9?
a) the expression describes the number that is 9 to the left of -9 on the number line
b) the expression describes the number that is 9 to the right of -9 on the number line
c) this expression equals -18
d) this expression equals 0
choose all answers that apply.

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?

Construct the graph that models the given situation

The? half-life of a radioactive substance is 20 years. if you start with some amount of this? substance, what fraction will remain in 120 ? years