5 (x + 8) = -10 what's the answer ​

Could somebody me with this radical simplification?

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?

Solve the inequaliy: (x^2+2)(x−2)^2(6−2x)> 0