A1 = -20 ; an = 0.5a n - 1? what are the first five terms​

Plz hurry evaluate the expression a+b where a=8 and b=19

Determine whether angle-angle-angle (aaa) is a valid means for establishing triangle congruence. if it is a valid criterion, explain why. if it is not valid, use geogebra to create a counterexample demonstrating that it doesn’t work and give an explanation. if you construct a counterexample, take a screenshot of your work, save it, and insert the image in the space below.

Barbara is tiling her craftroom floor with square tiles.she wants 6/10 of the square tiles to be red.if she used 18 red tiles,how many square tileswill be used to cover the floor?