Answer:
The image of 3 is not defined in the equation $x=3x+7$. This is because the equation is not solvable for $x$. In other words, there is no value of $x$ that will make both sides of the equation equal.
One way to see this is to subtract $3x$ from both sides of the equation. This gives us $0=x+7$. Now, if we subtract 7 from both sides of the equation, we get $-7=x$. However, this is not a valid solution, because $x$ cannot be negative.
Another way to see that the equation is not solvable is to graph it. The graph of the equation is a line that goes through the points $(-7,0)$ and $(0,7)$. However, there is no point on this line where the $x$-coordinate is equal to 3.
Therefore, the image of 3 in the equation $x=3x+7$ is not defined.
Explanation: