How do you convert standard form to vertex form?

What number should be added to both sides of the equation to complete this square? x^2-10x=7

I'm confused on this could anyone me and show me what i need to do to solve it.

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?