To shift a function down by a certain number of units, you subtract that number from the function's output.
Given the function \( h(x) = 5\sqrt{3x} + 10 \), to shift it down by 6 units, you would subtract 6 from the entire function:
\[ k(x) = h(x) - 6 = 5\sqrt{3x} + 10 - 6 \] \[ k(x) = 5\sqrt{3x} + 4 \]
Thus, the correct representation of shifting \( h(x) \) down by 6 units is:
\( k(x) = 5\sqrt{3x} + 4 \)
This means the correct choice from your options is:
m(x) = 5√(3x) + 4.