Your bookcase contains 6 novels, 6 biographies, and 6 textbooks. If you selected two books at random, What is the probability of selecting two different books in a row?

Find the sum of 4x^{2} -4+6 and -7^{2} +3x+1

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?

Find the distance between (7,-6) and (-3,-9)