Substitution
Another method for testing for equivalent expressions is to plug in numbers for the variables and see if the answers are the same.
Go through the lesson on substituting values into an algebraic expression and play the game
Here are two expressions:
| 4(x + 7) + 2 | 2x + 15 + 2x + 15 |
| 1. Plug in values
(not 0 or 1). Pick the number 2 for example. |
1. Plug in the same value as the first expression. |
| 2. Substitute 2 in
wherever there is an x: 4[(2) + 7] + 2. |
2. Substitute 2 wherever
there is an x. 2(2) + 15 + 2(2) + 15 |
3. This expression will simplify to 4(9) + 2 Which is 36 + 2 Which leaves the final answer of 38. |
3. This expression will simplify to 4 + 15 + 4 + 15 Add all your values together. The final answer is 38. |
Since the final answers are the same, the expressions are equivalent! |
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