I am the best right free point

The parabola opens: y=√x-4 (principal square root) up down right left

Onnie is considering doing some long term investing with money that she inherited. she would like to have $50,000 at the end of 30 years. approximately how much money would lonnie need to put into an account earning 6% interest compounded annually in order to meet her goal?

Write the equation in general quadratic form: plz !