Brianna’s teacher asks her which of these three expressions are equivalent to each otherExpression A9x−3x−4Expression B12x−4Expression C5x+x−4Brianna says that all three expressions are equivalent bec

Error in Brianna's thinking: Brianna assumes that all three expressions are equivalent because they have the same value of -4 when x = 0. However, this is not enough to prove that the expressions are equivalent for all values of x.

Equivalent expressions: Expression A and Expression B are equivalent.

Process: To show that two expressions are equivalent, we need to simplify them and show that they have the same value for all possible values of the variable.

Expression A: 9x/3x - 4 = (9x - 12x)/3x = -3x/3x = -1 Expression B: 12x - 4

Since Expression A simplifies to -1 and Expression B is already in its simplest form, we can see that they are not equivalent to Expression C, which has an additional term of 5x. Therefore, the answer is that only Expression A and Expression B are equivalent.