Some one help me please I’m struggling with 1-2 how do I work it out

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?

Write an equation in point-slope form for the line through the given point that has the given slope (-2,-7); m=-3/2

Which is the equation of a line perpendicular to the line with the equation 3x+4y=8