How to work it out and the answer for this question

If you use an x value of 3.5 you get that the right side is 49.875 which could feasibly be rounded to 50.  If you use an x value of 3.6 you get that the right side is 53.856 which is way too high.  To show your "working", just sub in 3.5 for each x: (3.5)^3 + 2(3.5)=50 and you'll get 49.875=50 (which it doesn't obviously, but it's as close as we are going to come since the directions told us to keep our number to one decimal place.)

Ithink the answer will be d yes