2 Original formula =4*(9-4+2* radical number 5)=20+8* radical number 5=20+8*2.236=37.888.

There is nothing wrong with the cube root of 3 -27 being -3, but the square root of the root number 8 1 is plus or minus 9. Open the square root again, -9 has no square root, and the square root of 9 is plus or minus 3, so the answer is C.