Answer:
![3(x - 7)(x+7)](https://img.qammunity.org/2021/formulas/mathematics/high-school/8qa6499anvfx79p2l774db7nw3p7sjmc9u.png)
Explanation:
To factor this, you must first take out the GCF (Greatest Common Factor), that
and -147 both have. The terms only have 3 in common, which can be divided with
![3x^2 - 147\\3(x^2 - 49)](https://img.qammunity.org/2021/formulas/mathematics/high-school/eupq16sm4xzh88naue2jmzl8f2q11jsga3.png)
However, we're still not done since 49 is a perfect square and
can be split into 2, like so:
![3(x - 7)(x+7)](https://img.qammunity.org/2021/formulas/mathematics/high-school/8qa6499anvfx79p2l774db7nw3p7sjmc9u.png)
If you're unsure about the final answer, you can multiply it all together to see if you got the original expression.