Question

Help pls I'm so confused

Answer 1

So you are given:
\[\large 3x^4-2x^2+15x^2-10\]
You can group the terms like so:
\[\large (3x^4+15x^2)+(-2x^2-10)\]
Factor out any common terms from both:
\[\large 3x^2(x^2+5)-2)(x^2+5) \]
Since these are the same, you can combine them:
\[\large 3x^2\color{red}{(x^2+5)}-2\color{red}{(x^2+5)} \]
You end up with
\[\Large (3x^2-2)(x^2+5) \]