To fill in the parts-whole model for the equation
\[ (3x^2 - 17x - 2) - (\underline{\quad}) = 10x^2 - 10x - 3, \]
we need to determine what the missing term (the subtracted expression) is that, when subtracted from \(3x^2 - 17x - 2\), will yield \(10x^2 - 10x - 3\).
Let's denote the missing expression as \(E\). We can rewrite the equation as:
\[ E = (3x^2 - 17x - 2) - (10x^2 - 10x - 3). \]
Now, we'll simplify the right-hand side by distributing the negative sign:
\[ E = 3x^2 - 17x - 2 - 10x^2 + 10x + 3. \]
Now, let's combine like terms:
- Combine \(3x^2\) and \(-10x^2\):
\[ 3x^2 - 10x^2 = -7x^2. \]
- Combine \(-17x\) and \(10x\):
\[ -17x + 10x = -7x. \]
- Combine \(-2\) and \(3\):
\[ -2 + 3 = 1. \]
Now, putting it all together, we get:
\[ E = -7x^2 - 7x + 1. \]
So the completed equation is:
\[ (3x^2 - 17x - 2) - (-7x^2 - 7x + 1) = 10x^2 - 10x - 3. \]
Thus, the part to fill in the blanks is
\[ \underline{-7x^2 - 7x + 1}. \]