Ayudaa por favor es para hoy tengo que entregarlo a las 4:00pm

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?

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

Twice the sum of a number and 4 is equal to three times the difference of the number and 7. find the number.