How do I do this (With instructions if you could) (Will give brainliest)

Marcus needs to rewrite f(x) = x2 + 6x + 4 in vertex form.

Astore has clearance items that have been marked down by 60%. they are having a sale, advertising an additional 55% off clearance items. what percent of the original price do you end up paying?

For what values of the variable x is the expression square root of 7x+14+ square root of 7-x a real number?