Answer: C) 25x^2 + 15x - 4
Step-by-Step Explanation:
To open double brackets we have to multiply each term in the first bracket with each term in the second bracket.
Therefore,
=> (5x - 1)(5x + 4)
= 5x * 5x + 5x * 4 - 1 * 5x - 1 * 4
= 25x^2 + 20x - 5x - 4
=> 25x^2 + 15x - 4
