Will mark brainlist to whoever gets it right.

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?

Terri makes a quilt using three sizes of fabric squares the side lenght of each fabric square is the square root of the area

Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9