4math questions 1.) a^2-10a=4 2.) x^2+20x-18=3 3.) (x-5)^2=1 4.) x^2-18x=65

Acomputer store buys a computer system at a cost of $370.80. the selling price was first at $ 618, but then the store advertised a 20 % markdown on the system. answer parts a and b. a. find the current sale price.