Question

Find the product:

(5x + 3y) (5x – 3y)

Answer 1

Given expression: (5x + 3y)(5x – 3y)

Step-wise calculation:

1. Recognise this as a product of the form (a + b)(a – b), which equals a² – b².

2. Here, a = 5x and b = 3y.

3. Apply the difference of squares formula:

(5x + 3y)(5x – 3y) = (5x)² – (3y)² 

4. Calculate the squares:

(5x)² = 25x² and (3y)² = 9y²

5. Substitute back:

25x² – 9y²