How many black keys will appear on a pipe organ with a total of 240 keys?

Thelime contains the point(-3,0) and parallel x-3y=3( show all work)

Graph y ≥ -x^2 - 1. click on the graph until the correct graph appears.

In the following diagram it is given that dec,ab || dc, ad || eb, and ad is congruent to bc. a)why isn't abc a parallelogram even though it has a pair of parallel sides and a pair of congruent sides b)explain why be must be congruent to bc. further explain what type of triangle this makes triangle abc and what it tells you about angle 1 and angle 2c) finally why must angle 3 be congruent to angle 1? further, explain why we know that angle 3 is congruent to angle 2