The function given is $f(x) = 10x$, and you're asked to find the y-intercept of $f(x) + 3$.

The y-intercept occurs where $x = 0$. So, to find the y-intercept, substitute $x = 0$ into the equation $f(x) + 3$.

$f(x) + 3 = 10x + 3$

When $x = 0$:

$f(0) + 3 = 10(0) + 3 = 0 + 3 = 3$

Therefore, the y-intercept is at $(0, 3)$.

Do you need more details or have any questions?

Here are some related questions for further exploration:

1. What is the slope of the line represented by $f(x) + 3$?
2. How would the graph of $f(x) + 3$ differ from the graph of $f(x)$?
3. What are the coordinates of the x-intercept of $f(x) + 3$?
4. How does shifting the function vertically affect its intercepts?
5. What is the domain and range of $f(x) + 3$?

Tip: Always check the impact of constants added or subtracted on the y-intercept, as it represents a vertical shift.