Answer :

To simplify the given expression [tex]\(\frac{\sqrt{-10} \cdot \sqrt{-20}}{1-\sqrt{-4}}\)[/tex], let's proceed step-by-step:

### Step 1: Simplify the Numerator
The numerator of the expression is [tex]\(\sqrt{-10} \cdot \sqrt{-20}\)[/tex].

1. Simplify [tex]\(\sqrt{-10}\)[/tex]:
[tex]\[ \sqrt{-10} = \sqrt{10} \cdot i \][/tex]
where [tex]\(i\)[/tex] is the imaginary unit.

2. Simplify [tex]\(\sqrt{-20}\)[/tex]:
[tex]\[ \sqrt{-20} = \sqrt{20} \cdot i \][/tex]

3. Multiply [tex]\(\sqrt{10} \cdot i\)[/tex] and [tex]\(\sqrt{20} \cdot i\)[/tex]:
[tex]\[ \sqrt{-10} \cdot \sqrt{-20} = (\sqrt{10} \cdot i) \cdot (\sqrt{20} \cdot i) = \sqrt{10} \cdot \sqrt{20} \cdot i^2 \][/tex]
Since [tex]\(i^2 = -1\)[/tex], the expression simplifies to:
[tex]\[ \sqrt{10} \cdot \sqrt{20} \cdot (-1) \][/tex]
[tex]\[ = -\sqrt{10 \cdot 20} \][/tex]
[tex]\[ = -\sqrt{200} \][/tex]
Since [tex]\(\sqrt{200} = \sqrt{100 \cdot 2} = 10\sqrt{2}\)[/tex], we have:
[tex]\[ -\sqrt{200} = -10\sqrt{2} \][/tex]
Numerically, [tex]\(-10\sqrt{2} \approx -14.142135623730953\)[/tex].

### Step 2: Simplify the Denominator
The denominator of the expression is [tex]\(1 - \sqrt{-4}\)[/tex].

1. Simplify [tex]\(\sqrt{-4}\)[/tex]:
[tex]\[ \sqrt{-4} = \sqrt{4} \cdot i = 2i \][/tex]

2. Form the whole denominator:
[tex]\[ 1 - \sqrt{-4} = 1 - 2i \][/tex]

### Step 3: Divide the Numerator by the Denominator
Now we need to divide [tex]\(-10\sqrt{2}\)[/tex] by [tex]\(1 - 2i\)[/tex].

Performing this division in complex number arithmetic, in rectangular form, we get:

The numerator is [tex]\(-14.142135623730953\)[/tex].
The denominator is [tex]\(1 - 2i\)[/tex].

Simplifying the division:
[tex]\[ \frac{-14.142135623730953}{1-2i} \approx -2.8284271247461907 - 5.6568542494923815i \][/tex]

### Conclusion
The simplified result of the given expression [tex]\(\frac{\sqrt{-10} \cdot \sqrt{-20}}{1 - \sqrt{-4}}\)[/tex] is:
[tex]\[ -2.8284271247461907 - 5.6568542494923815i \][/tex]