, and you know that and lie on the curve.

What you have been given in nonsense, as the exponential function never crosses the horizontal axis. So you can't have the values of being different sign...

Just to be sure:

Substituting these points gives two equations in two unknowns:

.

Dividing Equation 2 by Equation 1 gives:

.

This is clearly impossible since the exponential function is always positive.