Question

When expanding the brackets (2a-3b)²

Answer 1

4a² + 12ab + 9b²
where is the minus sign ?
4a² - 12ab + 9b²

Answer 2

When expanding (2a-3b)², we use the formula:

(a-b)² = a² - 2ab + b²

So, substituting 2a for a and -3b for b, we get:

(2a-3b)² = (2a)² - 2(2a)(-3b) + (-3b)²
= 4a² + 12ab + 9b²

Therefore, (2a-3b)² expands to 4a² + 12ab + 9b².

Answer 3

Apologies for the error in the previous answer. The correct expansion of (2a-3b)² is:

(2a-3b)² = (2a)² - 2(2a)(3b) + (-3b)²
= 4a² - 12ab + 9b²

So, the expansion of (2a-3b)² is 4a² - 12ab + 9b², with a negative sign between the second and third terms.