1. **State the problem:**
We are given the quadratic expression $$2x^2 - 6x - 20$$ and asked to fill in the gaps in the expression $$2x^2 - 6x - 20 = \square (x^2 - \square x - \square)$$
Then, we need to fully factorise $$2x^2 - 6x - 20$$ in the form $$a(x + b)(x + c)$$.
2. **Fill in the gaps:**
We start by factoring out the greatest common factor (GCF) from the quadratic expression.
The GCF of $$2x^2$$, $$-6x$$, and $$-20$$ is 2.
So, we write:
$$2x^2 - 6x - 20 = 2(x^2 - 3x - 10)$$
Thus, the filled gaps are:
- First gap: 2
- Second gap: 3
- Third gap: 10
3. **Factorise the quadratic inside the parentheses:**
We now factorise $$x^2 - 3x - 10$$.
We look for two numbers that multiply to $$-10$$ and add to $$-3$$.
These numbers are $$-5$$ and $$2$$ because:
$$-5 \times 2 = -10$$
$$-5 + 2 = -3$$
So,
$$x^2 - 3x - 10 = (x - 5)(x + 2)$$
4. **Write the full factorisation:**
Substitute back:
$$2(x^2 - 3x - 10) = 2(x - 5)(x + 2)$$
5. **Final answer:**
The fully factorised form is:
$$2(x - 5)(x + 2)$$
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**Summary:**
- Filled gaps: $$2, 3, 10$$
- Factorised form: $$2(x - 5)(x + 2)$$
Quadratic Factorisation 5D5F78
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