Which function has a vertex at the origin?

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?

Can some one explain how to slove specifically, what is the value of x? 0.9(x+1.4)-2.3+0.1x=1.6 enter the answer as a decimal in the box. x= ?

Rewrite the following quadratic functions in intercept or factored form. show your work. f(x) = 3x^2 - 12