X²-3x-10=0
x²-(5-2)x-10=0
x²-5x+2x-10=0
x(x-5)+2(x-5)
(x-5)(x+2)
Your problem statement needs a bit of correction:
"<span>Y= -16t^2 +400, where t represents the number OF SECONDS after the camera is dropped. How long will it BE before Kay sees the splash from the camera hitting the water?"
Set y = -16t^2 + 400 = 0. We assume that 400 and 0 represent feet (English system).
Then 16t^2 = 400, and so 25 = t^2. Only the positive square root makes sense here, and that root is 5 (seconds).</span>
The answer is 20%
[(150 - 125) / 125] × 100% = 0.2 × 100% = 20%
hope that i have helped!