Answer:
Solve for x^2/2 - 10x = 0
<=> x^2 - 20x = 0
<=> x(x - 20) =0
<=> x = 0(invalid), x = 20
=> After 20s, Rui reaches his lowest altitude
Hello,
x = 10
Step-by-step explanation:
[tex]-\frac{-10}{2\frac{1}{2} } = \frac{10}{1} = 10[/tex]
or :
d(0) = 0
and
d(20) = 0
[tex]\frac{0 + 20}{2} = 10[/tex]
