Kari uses substitution to decide whether x2+x is equivalent to x (2x+1). She says the expressions are equivalent because they have the same value when x=0. Is Kari correct? Explain.

Question

Edith Floyd

Mathematics

31 August, 11:18

Kari uses substitution to decide whether x2+x is equivalent to x (2x+1). She says the expressions are equivalent because they have the same value when x=0. Is Kari correct? Explain.

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Zoie · Answer 1

Kari is not correct. Plug in any value other than 0 for these and the answers you get will not be equal, simple as that. (ex. If x = 3, x² + x = 12 and x (2x+1) = 21)

x = 0 would be a solution to the set of equations, but the question here is are all solutions valid, which is not so.