URGENT! What is the solution set of the following system of equations?

x + y = 0

x - y + 2 = 0

Ivan began dividing g2  – 6 by g + 1, noting that . he started by placing g in the quotient, as shown below.what is g2  – 6 divided by g + 1? g –  1 –  g + 1  – g  –  7 + g  –  5  + 

Aman is 6 feet 3 inches tall. the top of his shadow touches a fire hydrant that is 13 feet 6 inches away. what is the angle of elevation from the base of the fire hydrant to the top of the man's head?

Afarm that has 4 x 10^2 acres has 1.2 x 10^5 cattle. what is the average number of cattle per acre? write the answer in scientific notation. answere asap