If 3x cubed plus 7 equals 250 then x equals

Subtract seven to get 3x cubed equals 243. Divide by three to get x cubed equals 81. This would not be a perfect cube. The keyed solution expects x equals 2 using a different reading 3x plus 7 equals 250 then x equals 81. Here we follow the key which lists option C as the answer in this paper.