What is a linear factor of f(x)=3x^4+15x^3+15x^2-15x-18

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?

Acompany that manufactures and sells guitars made changes in their product range. from the start they had 20 models. then they reduced the number of models to 15. as a result, the company enjoyed a 10% increase in turnover. - how much did the stock level change? in (%)

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