Look at #3 and #6 plz help with those question

Points a, b, and c form a triangle. complete the statements to prove that the sum of the interior angles of triangle abc is 180

Find the solution(s) to the system of equations. select all that apply y=x^2-1 y=2x-2

2. using calculations based on a perpetual inventory system, determine the inventory balance altira would report in its august 31, 2021, balance sheet and the cost of goods sold it would report in its august 2021 income statement using the average cost method. (round "average cost per unit" to 2 decimal places.)