Tyler is using the distributive property on the expression 9 - 4(5x – 6). Here is his

work:

9 - 4(5x - 6)

9+(-4)(5x +-6)

9 +-20x +-6

3 – 20x

Mai thinks Tyler's answer is incorrect. She says, "If expressions are equivalent then

they are equal for any value of the variable. Why don't you try to substitute the same

value for x in all the equations and see where they are not equal?"

a. Find the step where Tyler made an error.

b. Explain what he did wrong.

c. Correct Tyler's work.

Asays "we are both knaves" and b says nothing. exercises 24–31 relate to inhabitants of an island on which there are three kinds of people: knights who always tell the truth, knaves who always lie, and spies (called normals by smullyan [sm78]) who can either lie or tell the truth. you encounter three people, a, b, and c. you know one of these people is a knight, one is a knave, and one is a spy. each of the three people knows the type of person each of other two is. for each of these situations, if possible, determine whether there is a unique solution and determine who the knave, knight, and spy are. when there is no unique solution, list all possible solutions or state that there are no solutions. 24. a says "c is the knave," b says, "a is the knight," and c says "i am the spy."