Alana and petra go to a used book sale, where every book is the same price. alana buys 5 books and petra buys 4 books. they run into their friend angus, who really loves to read, and discover that he has bought 19 books. angus received a $10 discount, but he still spent $5 more than alana and petra combined. how much does one book cost?

Select all the correct answers.natalie buys a new car. in the first month, the odometer on the car records 800 miles. from past experience, she expects to drive 900 miles per monthselect all the functions that can be used to find the number of miles, f(n), recorded on the odometer after n months.of(n) = 800n + 100f(n) = 9001 - 100f(n) = 900n + 800(1) = 800; }(n) = f(n - 1) + 900, for n > 2f(1) = 800; 1(n) = f(n − 1) + 100, for n > 2(1) = 900; }(n) = f(n - 1) + 800, for n > 2

Demonstrate the proof of your new polynomial identity through an algebraic proof and a numerical proof in an engaging way! make it so the whole world wants to purchase your polynomial identity and can't imagine living without it! you must: label and display your new polynomial identity prove that it is true through an algebraic proof, identifying each step demonstrate that your polynomial identity works on numerical relationships create your own using the columns below. see what happens when different binomials or trinomials are combined. square one factor from column a and add it to one factor from column b to develop your own identity. column a column b (x − y) (x2 + 2xy + y2) (x + y) (x2 − 2xy + y2) (y + x) (ax + b) (y − x) (cy + d)

The sum of two numbers is 86, and their difference is 20. find the two numbers