Answer:
The 4th choice: The graph of the equation has roots at x = -b/a and x = -d/c
Explanation:
If we have an equation of the form

then it must be that either

or

The first equation gives

and the second equation gives

Hence, the roots of the equation turn out to be

Therefore, we conclude that the equation of the form (ax + b) (cx + d) tells us about the roots of the function, and hence, choice 4 is correct.