Is the following an algebraic expression: 18r + (r ÷ 8) - 13

Which term best describes the association between variables a and b

Use the frequency distribution, which shows the number of american voters (in millions) according to age, to find the probability that a voter chosen at random is in the 18 to 20 years old age range. ages frequency 18 to 20 5.9 21 to 24 7.7 25 to 34 20.4 35 to 44 25.1 45 to 64 54.4 65 and over 27.7 the probability that a voter chosen at random is in the 18 to 20 years old age range is nothing. (round to three decimal places as needed.)

Ab and bc form a right angle at point b. if a= (-3,-1) and b= (4,4) what is the equation of bc?