Factorisation Check 5C9Ccc
1. **Factorise the expression 9p^2 - q^2**
This is a difference of squares, which follows the formula:
$$a^2 - b^2 = (a - b)(a + b)$$
Here, $a = 3p$ and $b = q$.
So,
$$9p^2 - q^2 = (3p - q)(3p + q)$$
2. **Check the equation (c + 2d)^2 = (c + 2d)(3c - 7d)**
First, expand the left side:
$$(c + 2d)^2 = (c + 2d)(c + 2d) = c^2 + 4cd + 4d^2$$
Now, expand the right side:
$$(c + 2d)(3c - 7d) = 3c^2 - 7cd + 6cd - 14d^2 = 3c^2 - cd - 14d^2$$
Since the two sides are not equal, the given equation is incorrect as stated.
3. **Factorise 32a^2 - 98b^2**
First, factor out the greatest common factor (GCF):
$$2(16a^2 - 49b^2)$$
Notice $16a^2 - 49b^2$ is a difference of squares:
$$16a^2 - 49b^2 = (4a)^2 - (7b)^2 = (4a - 7b)(4a + 7b)$$
So the full factorisation is:
$$2(4a - 7b)(4a + 7b)$$
**Final answers for Q1:**
- a) $$(3p - q)(3p + q)$$
- b) The equation is not true as given.
- c) $$2(4a - 7b)(4a + 7b)$$