Suppose y varies directly with x. If y = –4 when x = 8, what is the equation of direct variation? Complete the steps to write the equation of direct variation.

Start with the equation of direct variation y = kx.
Substitute in the given values for x and y to get
.
Solve for k to get
.
Write the direct variation equation with the value found for k. The equation is
.

For the function, f(x) = -5x 2, find f(-4).

Tom is making a punch that contains 80% cranberry juice and the rest ginger ale. the punch has 2 liters of ginger ale. part a: write an equation using one variable that can be used to find the total number of liters of cranberry juice and ginger ale in the punch. define the variable used in the equation and solve the equation. hint: 0.8x represents the number of liters of cranberry juice in the punch. (5 points) part b: how many liters of cranberry juice are present in the punch? show your work.

What is the approximate value of  x  in the equation below.–3.396–0.7080.3040.955