Answer:
f(x) = x - 6
Explanation:
The parent linear function of f(x) = x would go through the origin of (0,0) and has a slope of '1'. If you move the function down by 6 units, you are moving the y-intercept (the points where it crosses the y-axis) down by 6 units to (0, -6). This would make the parent function:
f(x) = x - 6, where slope = 1 and the y-intercept = -6.