What does the expression 6.50a + 3.25b + 4.65a + 2.25c + 1.75b represent in the context of this problem?

This is so harddd! solve. 1 + 1 = solve 4 + 4 = solve 3 x 3

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?

Which of the binomials below is a factor of this trinominal? x^2-13+30