Pls can any one help me with question two pls Someone kind answered question one for me soo can u pls answer question two for me pls

Can someone check if i did this correct. it’s number 4 if you’re wondering.

Measure of angles 31 (x+4) (3x+9) me

Me! i will mark brainliest! i don't get polynomials and all that other stuff. so this question is really hard. multiply and simplify.(x - 4) (x^2 – 5x – 6)show your