Question

Help
4. What is the completed factored form of 5x^2 – 45?

5(x + 3)(x – 3)

5(x – 3)^2

5(x^2 – 9)

5(x + 9)(x – 9)

Answer 1

Tell us what you think so we can see where you got stuck

Answer 2

I dont know how to solve the problem @Crixpack

Answer 3

okay, but do you understand factorizing in general?

Answer 4

yes

Answer 5

okay, can you spot any common factors between 5x^2 and 45?

Answer 6

\[\large 5x^2-45=\color{red}{5}x^2-\color{red}{5}\cdot9=5(x^2-9)=
5(x+3)(x-3). \]