<|system|>
What number must we add to $3-5i$ to get $2+7i$? Here, $i^2 = -1.$</s>.
<|user|>
Can you answer based on context?
<|assistant|>
We seek the number $z$ such that $3-5i + z = 2+7i$, so $z = 2+7i-3+5i = -1+12i$.