For each party will operation write the letter that corresponds to the resulting expression from the list (5x^2+2x+1)+(6x^2-3x+9) is equivalent to expression blank. (-3x^2+6-12)+(5x+9) is equivalent to the expression blank. (8x+16)-(3x^2-3x-15) is Equivalent toexpression blank. ((5x^2+23x-7)-(x^2-4x+21) is equivalent to the expression blank. 

Sanya noticed that the temperature was falling at a steady rate of 1.4 degrees every hour from the time that she first checked her outdoor thermometer. by 6 a.m., the temperature had fallen 21 degrees. which expression can you use to find how many hours earlier she had first checked the thermometer?

Aubrey read 29 books and eli read 52 books what number is equal to the number of books aubrey read?

Amira is painting a rectangular banner 2 1/4 yards wide. the banner will have a blue background. amira has enough paint to cover 1 1/2 square yards of the wall. the school colors are blue and yellow, so amira wants to add yellow rectangles on the left and right sides of the blue rectangle. the yellow rectangles will each be 3/4 yards wide and the same height as the blue rectangle. what will be the total area of the two yellow rectangles?