Answer:
2/(7a) < x < 7
Step-by-step explanation:
The product of roots of ax² +bx +c is c/a. In this case, that means the second root of the equation is ...
... 2/(7a)
Since a < 0, the parabola opens downward and 2/(7a) < 0. The quadratic function will be positive between the two roots, on the interval ...
... 2/(7a) < x < 7
