Question

How did i work this out?

Answer 1

knowing the answer is between 3 & 4 plug those as x and see what you get for answers than adjust the number accordingly

3^3+2(3) = 33 so its higher than 3

4^3 + 2(4) = 72 so it is lower than 4

try the middle so try 3.5

3.5^3 + 2(3.5) = 49.875

question states use 1 decimal place so now try 3.6

3.6^3+2(3.6) = 53.856

3.5 is closest