40% of what number is 82

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.

Which equation shows the quadratic formula used correctly to solve 5x2 + 3x -4 0 for x? cos -3+ v (3) 2-4() 2(5) 3+ |(3)² +4() 205) 3+ (3) 2-4() -3+ v (3)² +4()

Aright triangle has an area of 21 m2. the dimensions of the triangle are increased by a scale factor of 4. what is the area of the new triangle