Write an equation that is linear but not standard form

The verbal translation for the difference of m and 7 increased by 15

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?

Could someone me with this question i’ve been stuck on it for 20 minutes