Question

Factor completely. 5x2 - 45 A. 5(x + 3)(x - 3) B. 5(x2 - 45) C. 5(x - 9)(x + 9) D. (5x + 9)(x - 5)

Answer 1

Answer:

The correct answer is A. 5(x + 3)(x - 3)

Step-by-step explanation:

In order to solve this, we start by pulling out the greatest common factor.

5x^2 - 45

5(x^2 - 9)

Now we can use the difference of two squares to factor the rest of the equation.

5(x + 3)(x - 3)

Answer 2

Answer:

A. 5(x + 3)(x - 3)

Step-by-step explanation:

Given equation is,

$5x^2-45$

$=5x^2-5\times 9$

$=5(x^2-9)$

$=5(x^2-(3)^2)$  

$=5(x+3)(x-3)$         ( a² - b² = (a+b)(a-b) )

Since, further factorization is not possible,

Hence, the required factored form of the given expression is,

$5(x+3)(x-3)$

Option A is correct.