To evaluate the expression \((13 + -\sqrt{225}) - (\sqrt{49} - 2i)\), we will first simplify each part step by step.
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\( \sqrt{225} = 15 \), so \( -\sqrt{225} = -15 \). Thus, \( 13 + -\sqrt{225} = 13 - 15 = -2 \).
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Next, \( \sqrt{49} = 7 \). Therefore, \( \sqrt{49} - 2i = 7 - 2i \).
Now, we can substitute these results back into the original expression:
\[ (-2) - (7 - 2i) \]
This can be rewritten as:
\[ -2 - 7 + 2i \]
Combining the real parts:
\[ -2 - 7 = -9 \]
So the expression simplifies to:
\[ -9 + 2i \]
Finally, the answer in the form \( a + bi \) is:
\[ \boxed{-9 + 2i} \]