Answer:
B
Step-by-step explanation:
-t²+4t+5=0
t²-4t-5=0
t²-5t+t-5=0
t(t-5)+1(t-5)=0
(t-5)(t+1)=0
t=5,-1
when t=0,d=5
actual time it it is in air=5-1=4 seconds.
<span>The roof is higher than the ladder can reach
10^2-1.5^2=h^2
h=sqrt(100-2.25)=9.89 feet
distance to the roof= 12-9.89</span>
The formula for conditional probability is:


The correct answer choice is therefore D) 91%
Answer: m1 = 4
m2 = 5
m3 = 2
Step-by-step explanation:
given (21/11, 6/11) = m1 (-1/3) + m2 (3, -2) + m3 (5, 2)
= (-m1 + 3m2 + 5m3) / 11 = 21/11
= (3m1 + (-2)m2 + 2m3) / 11 = 6/11
so that m1 + m2 +m3 = 11
-m1 + 3m2 + 5m3 = 21
3m1 - 2m2 + 2m3 = 6
from this, we get the augmented matrix as
\left[\begin{array}{cccc}-1&1&1&11\\-1&3&5&21\\3&-2&2&6\end{array}\right]
= \left[\begin{array{cccc}-1&1&1&11\\0&4&6&32\\0&-5&-1&-27\end{array}\right] \left \{ {{R2=R2 + R1} \atop {R3=R3 -3R1 }]} \right.
= \left[\begin{array}{cccc}-1&1&1&11\\0&1&3/2&8\\0&-5&-1&-27\end{array}\right]
= \left[\begin{array}{cccc}-1&1&1&11\\0&1&3/2&8\\0&0&13/2&13\end{array}\right]
(R3 = R3 + 5R2)
this gives m1 + m2 + m3 = 11
m2 + 3/2 m3 = 8
13/2 m3 = 8
13/2 m3 = 13
m3 = 2
m2 = 8 -3/2 (2) = 5
= m1 = 11- 5 - 2 = 4
this gives
m1 = 4
m2 = 5
m3 = 2