To shift the graph of $y = \sqrt{x}$ to the left by 4 units, we replace $x$ with $x + 4$ in the function. This is because a horizontal shift to the left by $h$ units is represented by $x + h$.

Thus, the new function will be:

$y = \sqrt{x + 4}$

This is the equation of the function whose graph is the same as $y = \sqrt{x}$ but shifted to the left by 4 units.

Would you like further details or have any questions?

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Here are 5 related questions:

1. How do you shift a graph to the right by a certain number of units?
2. What happens to the graph if you shift $y = \sqrt{x}$ down by 3 units?
3. What is the domain of the function $y = \sqrt{x+4}$?
4. How does the graph of $y = \sqrt{x}$ change if it's reflected over the x-axis?
5. How do you shift a function both horizontally and vertically at the same time?

Tip: Horizontal shifts are always counterintuitive: adding to $x$ shifts the graph left, and subtracting from $x$ shifts it right.