4n² - 16n - 84 = 0
Multiply both sides by 1/4 :
n² - 4n - 21 = 0
Add 21 to both sides:
n² - 4n = 21
Complete the square by adding 4 to both sides:
n² - 4n + 4 = 25
(n - 2)² = 25
Solve for n :
n - 2 = ± √25
n - 2 = ± 5
n = 2 ± 5
Then n = 2 + 5 = 7 or n = 2 - 5 = -3.
The graph is not proportional because it doesn’t go though the origin aka (0,0)
<span>The work surface should be between 20 and 30 inches deep and at least 24 inches wide. For maximum flexibility, the height should be that of a conventional writing desk, about 28 to 30 inches, with the keyboard resting on an adjustable shelf. Seat height should be adjustable from 16 to 20 inches</span>
Answer:
8 seconds.
Step-by-step explanation:
To solve this question, we need to find the time, 
, when 
, that is, when the height of the object above the ground is 0 feet.
Substituting 
feet per second and gives the quadratic:
Since 128 is divisible by 16, it can be reduced to 
.
We must now solve for .
We can easily see that one answer to the equation is 0,
(we need not concern ourselves with the 16 outside of the parenthesis as in the equation above, since 16 multiplied by 0 is 0). However this is the time the object is released into the air.
The second answer, 
is also easy to see by inspection:
.
Therefore the object lands 8 seconds after it is thrown.
Answer:
144-36=108
Square root 108 = 10.4cm (cb)
Soh Cah toa
Sin(55) =o/h
=10.4/h
xh
H x sin55 =10.4
÷sin55
H= 10.4/sin55
H=12.7cm
CD is 12.7cm to 3 s.f.
