Question 377706
a)  The leading term of the polynomial if the factors were multiplied out is {{{3x^3}}}.  Thus as x approaches {{{-infinity}}}, f(x) goes to {{{-infinity}}}. Similarly, as x approaches {{{infinity}}}, f(x) goes to {{{infinity}}}.

b)  The x-intercepts correspond to the roots -4 and 5.  -4 is a single root, and so it has to cross the x-axis (from - to +).  5 is a double root ( or multiplicity 2), and so it turns and touches the x-axis (it stays on or ABOVE the x-axis).

c) When x = 0, {{{f(0) = 3*(0+4)*(0-5)^2 = 3*4*25 = 300}}}.  That is the y-intercept.