How do you write the sum of a number and 5 divided by 20 is 5 as an equation?

What is the quadric regression equation that fits these data

Which is f(5) for the function –2x2 + 2x - 3?

How many liters of peroxide should be added to 12 liters of an 8% peroxide solution so that the resulting solution contains 16% peroxide?   original added new amount of peroxide 0.96 liters x 0.96 + x amount of solution 12 liters x 12 + x 0.18 liter 1.14 liters 1.92 liters 2.10 liters