HELP PLSss i beg

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?

What are the soultion(s) to the quadratic equation 40- x^2=0

For the equations below which statement is true ? -2x=14 6x=-42