Question

PLEASE HELP!!!! I’m about to rip my hair out over this.

Answer 1

Step-by-step explanation:

1. The equation graph is a parabola, so the maximum height will be the vertex of the parabola. You can find the vertex coordinate t using the formula:

t = -b/2a

t = -18/2•(-4.9)

t = -18/-9.8

t = 1.84 seconds

2. The height of the ground is 0, so the balls hit the ground when the equation result is 0:

0 = -4.9t²+18t+10

Now you solve it using Bhaskara:

Δ = b² -4ac

Δ = 18² -4•(-4.9)•10

Δ = 520

t = (-b ±√Δ)/2a

t = (-18 ± √520)/2•(-4.9)

t1 = (-18 - 20.8)/-9.8

t1 = 3.96 seconds

t2 = (-18 +20.8)/-9.8

t2 = -0.28

Doesn't exist negative time, so we pick the first value found, t = 3.96 seconds

3. Now you just need to put 3 in place of t to find the result:

h = -4.9•3² +18•3 +10

h = -4.9•9 + 54 + 10

h = -44.1 + 64

h = 19.9 meters

4. You just need to put 1 in place of t to find the height:

h = -4.9•1²+12

h = -4.9+12

h = 7.1 meters