Question

Anna is given the equation 5 + 3x = 3x + 5

The replacement set is {1, 2, 3, 4}
Anna says the solution is {2}, but the teacher marked her problem incorrect. Explain what the answer should be and why. Why do you think this is?

Answer 1

There are infinite possibilities for x

Explanation:

5 + 3x = 3x + 5

-5 -5

3x = 3x

÷3 ÷3

x = x

Therefore, you can put any replacement to x, and the equation would be true.