What expression can only give you an amount that is possible

Jamie is hiking up a small mountain. he climbs up at a constant rate of 300 feet/hour until he reaches the peak at 1,500 feet. after that, he hikes down at the same rate to the base of the mountain. the equation that models jamie’s elevation, e, after t hours is e = . jamie’s elevation will be 600 feet after hours and after hours.

Solve each quadratic equation by factoring and using the zero product property. x^2 + 18x = 9x

Ineed to find the answer to number 2