Question

A math class is having a discussion on how to determine if the expressions 4x-x+5 and 8-3x-3 are equivalent using

substitution. The class has suggested four different methods.
Which describes the correct method?
O Both expressions should be evaluated with one value. If the final values of the expressions are both positive, then the two
expressions must be equivalent.
Both expressions should be evaluated with one value. If the final values of the expressions are the same, then the two
expressions must be equivalent.
Both expressions should be evaluated with two different values. If for each substituted value, the final values of the
expressions are positive, then the two expressions must be equivalent.
O Both expressions should be evaluated with two different values. If for each substituted value, the final values of the
expressions are the same, then the two expressions must be equivalent.
6:55 PM
5/15/2020
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Answer 1

Both expressions should be evaluated with two different values. If for each substituted value, the final values of the expressions are the same, then the two expressions must be equivalent.

Explanation:

Both expressions are linear expressions. It takes 2 points to define a line. If the lines defined by each expression go through the same two points, then the expressions are equivalent.

If the expressions have the same value for two different variable values, they are equivalent. (choice D)

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Additional comment

One more point is needed than the degree of the polynomial expression. That is, quadratic (degree 2) expressions will be equivalent if they go through the same 2+1 = 3 points.