How do u do numbers 6 and 7? plz !

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?

Sorry guys but as you have a small brain

Before simplifying, how many terms are there in the expression 2x - 5y + 3 + x?