12. The difference of a linear function and a linear function is an integer.
13. The sum of a linear function and a quadratic function is a quadratic function.
Indicate if the statement is true or false. If it is false, find a counterexample to prove the claim is
false. (Recall that a set of number is closed under an operation if it will always produce another
number in the same set.)
14. The set of irrational numbers is closed under addition.
15. The set of integers is closed under addition and multiplication.
16. The set of irrational numbers is closed under multiplication.
Go
Find the product of each pair of conjugates.
17. (x-7) (x +,7)
19. (52 +3) (52 – 3)
21. (8 + √5) (8-√5)
18. (2x +9) (2x - 9)
20. (a - b) (a + b)
22 (2-√7) (2+√7)