Answer:
x = -2/15.
Step-by-step explanation:
Finding the second derivative:
f'(x) = 15x^2 +4x - 3
f"(x) = 30x + 4
30x + 4 = 0 for a point of inflection
x = -4/30 = -2/15
So 30x + 4 is negative up to x = -2/15 and positive thereafter.
So the curve passes from concave downward to concave upward at x = -2/15.
37.8 because you multiply 3 by 12.6 i got 12.6 by dividing 63 by 5
The red marble is farthest from the target.