(HELP NEEDED) Which expression is equivalent to (6x3+3x2+8)+(2x2−9x+10)? A. 6x3+5x2−9x+18

B. 5x4+6x3−9x+18

C. 6x3+x2+9x−2

D. 8x5−6x3+18

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?

Quadrilateral abcd in the figure below represents a scaled-down model of a walkway around a historic site. quadrilateral efgh represents the actual walkway. abcd is similar to efgh. what is the total length, in feet of the actual walkway?

Susie wants to take her friend out for lunch.she wants to spend $9.75 each person. how much will she spend in all.