## 11.59

Vanessa Reyes_1K
Posts: 60
Joined: Fri Sep 28, 2018 12:28 am

### 11.59

After using the quadratic to solve for x, how do we know which outcome is valid if both numbers are positive?

Eshwar Venkat 1F
Posts: 32
Joined: Fri Sep 28, 2018 12:22 am

### Re: 11.59

To check, you can plug the two x values back into the ICE table. In cases like this, usually when you plug in the larger x value, it results in the equilibrium concentrations of both reactants being less than 0, which cannot happen.

Gary Qiao 1D
Posts: 66
Joined: Fri Sep 28, 2018 12:26 am

### Re: 11.59

If you plug in the larger positive x value, you will find that the equilibrium concentrations of the reactants are negative, and that is not possible, meaning that value can be disregarded. Therefore, there would be only one valid x value.

Ian Marquez 2K
Posts: 66
Joined: Fri Sep 28, 2018 12:16 am
Been upvoted: 2 times

### Re: 11.59

For the two options, if both are positive, plug it into the ICE table and make sure that your equilibrium concentration is still positive. If x is too large then this will be negative which cannot happen. In any case, it is good to check both solutions if unsure, especially if both are positive values.