To find the area of the rectangle given the expressions \(3x^3\) and \(-4x^3 + 5\), we need to multiply these two expressions together:
\[ \text{Area} = (3x^3)(-4x^3 + 5) \]
Now, we will distribute \(3x^3\) to both terms in the second expression:
\[ \text{Area} = 3x^3 \cdot (-4x^3) + 3x^3 \cdot 5 \]
Calculating each part:
- \(3x^3 \cdot (-4x^3) = -12x^{3 + 3} = -12x^6\)
- \(3x^3 \cdot 5 = 15x^3\)
Now combine these results:
\[ \text{Area} = -12x^6 + 15x^3 \]
Thus, the area of the rectangle is:
\[ -12x^6 + 15x^3 \]
From the options provided, the correct response is:
−12x^6 + 15x^3.