A diver dives from a 10 m springboard. The equation
f(t)=−4.9t2+4t+10
models her height above the pool at time t in seconds. At what time does she enter the water?

0.8163265306

Step-by-step explanation

here f(t) is distance which is 10m.

so

10= -4.9t²+4t+10

then solve this

-4.9t²+4t=0

-4.9t+4=0

4.9t=4

t=4÷4.9

time is 0.8163265306 seconds

the answer is d. (1.2, -4.7) on edgn

hope this !