To solve the equation \( -x^{3/2} = -27 \), we start by removing the negative sign from both sides:
\[ x^{3/2} = 27 \]
Next, to eliminate the exponent \( \frac{3}{2} \), we can raise both sides to the power of \( \frac{2}{3} \):
\[ x = 27^{\frac{2}{3}} \]
First, we will find \( 27^{\frac{1}{3}} \):
\[ 27^{\frac{1}{3}} = 3 \quad (\text{since } 3^3 = 27) \]
Now we square that result:
\[ 27^{\frac{2}{3}} = (27^{\frac{1}{3}})^2 = 3^2 = 9 \]
Thus, the solution is:
\[ x = 9 \]
So the correct answer is:
9.