Answer: Explain why 2 + 3(x � 2) = 5x � 10 (*) is not true identity.
It is because the left part is
2 + 3x - 6 = 3x - 4,
while the right side is 5x - 10.
The left side expression differs from that of the right side.
Therefore, (*) is not an identity.
We even can go further and write a hypothetical equation
3x - 4 = 5x - 10
which implies
2x = 6 and then x = 3.
So, the two original expressions are equal only at x = 3, but they are not equal identically as functions.