Question

(4₊√₋81)₋(9₊√₋9) i cant resolve this equation. thanks for help

Answer 1

The question can't be solved because we can't have negative sign under square root

Answer 2

Answer:

 -5 +6i

Step-by-step explanation:

Square roots of negative numbers are imaginary. This is asking for the difference of two complex numbers. A suitable calculator can show you what that is.

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simplify radicals

We know that √(-1) ≜ i. This means the radicals can be simplified to ...

  $\sqrt{-81}=\sqrt{9^2(-1)}=9\sqrt{-1}=9i\\\\\sqrt{-9}=\sqrt{3^2(-1)}=3\sqrt{-1}=3i$

So the expression becomes ...

  (4 +9i) -(9 +3i)

combine terms

Like terms can be combined in the usual way. For the purpose here, i can be treated as though it were a variable.

  (4 +9i) -(9 +3i) = 4 +9i -9 -3i

  = (4 -9) +(9 -3)i

  = -5 +6i