What is four fifths equivalent to

What is the missing constant term in the perfect square that starts with x^2 -20x

Achemist has 200 ml of a 10% sucrose solution. she adds x ml of a 40% sucrose solution. the percent concentration, y, of the final mixture is given by the rational function: the chemist needs the concentration of the final mixture to be 30%. how many milliliters of the 40% solution should she add to the 10% solution to get this concentration?

Atriangle with all sides of equal length is a/an triangle. a. right b. scalene c. equilateral d. isosceles