What is the solution to the equation x over 2+10 equals -8

Can someone check my answer? you : )

Using the quadratic formula find the zeros of the given polynomial -5x^2+3x-11

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.