Please answer BOTH questions

46.28, 193.75

Step-by-step explanation:

The first one you add (((2.5+4.7)x3.05)+1.18)x2. And the second one you (7.50+0.25)x25.

Set the given equation equal to zero (0), since that's the height of the rock when it hits the water:

0 = -16(x^2 - 3x - 18)  (Note:  Please write x^2 to denote "square of x.")

Solving this equation for x, we get:

0 = -16(x-6)(x+3), and x=-3 or x=6.  Since x represents time, discard the negative value x=-3.

The rock hits the water after 6 seconds.