Given the function P(x)=x33x24x\displaystyle {P}{\left({x}\right)}={x}^{{3}}-{3}{x}^{{2}}-{4}{x}, find
its y\displaystyle {y}-intercept is  
its x\displaystyle {x}-intercepts are x1=\displaystyle {x}_{{1}}=   , x2=\displaystyle {x}_{{2}}=   and x3=\displaystyle {x}_{{3}}=   with x1<x2<x3\displaystyle {x}_{{1}}<{x}_{{2}}<{x}_{{3}}
When x\displaystyle {x}\to\infty, y\displaystyle {y}\to \displaystyle \infty (Input + or - for the answer)
When x\displaystyle {x}\to-\infty, y\displaystyle {y}\to \displaystyle \infty (Input + or - for the answer)