Please help, I'll be giving brainliest. Prove that the rational numbers are closed under addition. Please let me know if I'm correct, and if not what the answer should be, I'll be giving brainliest.

What is the area of triangle abc if a = 8, b = 11, and c = 15?

Drag each equation to the correct location on the table. for each equation, determine the number of solutions and place on the appropriate field in the table.

Agrid shows the positions of a subway stop and your house. the subway stop is located at (-5,2) and your house is located at (-9,9). what is the distance, to the nearest unit, between your house and the subway stop?