Answer:
[tex]3(x - 7)(x+7)[/tex]
Step-by-step explanation:
To factor this, you must first take out the GCF (Greatest Common Factor), that [tex]3x^2[/tex] and -147 both have. The terms only have 3 in common, which can be divided with
[tex]3x^2 - 147\\3(x^2 - 49)[/tex]
However, we're still not done since 49 is a perfect square and [tex](x^2 - 49)[/tex] can be split into 2, like so:
[tex]3(x - 7)(x+7)[/tex]
If you're unsure about the final answer, you can multiply it all together to see if you got the original expression.
