Answer:
I think it is F
Step-by-step explanation:
Hello,
Use the factoration
a^2 - b^2 = (a - b)(a + b)
Then,
x^2 - 81 = x^2 - 9^2
x^2 - 9^2 = ( x - 9).(x + 9)
Then,
Lim (x^2- 81) /(x+9)
= Lim (x -9)(x+9)/(x+9)
Simplity x + 9
Lim (x -9)
Now replace x = -9
Lim ( -9 -9)
Lim -18 = -18
_______________
The second method without using factorization would be to calculate the limit by the hospital rule.
Lim f(x)/g(x) = lim f(x)'/g(x)'
Where,
f(x)' and g(x)' are the derivates.
Let f(x) = x^2 -81
f(x)' = 2x + 0
f(x)' = 2x
Let g(x) = x +9
g(x)' = 1 + 0
g(x)' = 1
Then the Lim stay:
Lim (x^2 -81)/(x+9) = Lim 2x /1
Now replace x = -9
Lim 2×-9 = Lim -18
= -18
Answer:
2.25 (or 
) g/mL
<u>Skills needed: Density</u>
Step-by-step explanation:
1) Briefly, let's cover what density is:
- It is 
- Measures the mass per unit of volume
- In this situation the formula for density is: 
---> 
is the final mass
---> 
is the initial mass
---> 
is the final volume
---> 
is the initial volume
2) In this case, we start out with a mass of 180 grams as stated in the problem, and also 50 mL of water initially.
This means that:
- is 180 g
- is 50 mL
3) Also, we end up with 270 g in mass, and 90 mL of water finally.
- is 270g
- is 90 mL
4) We can find density by substitute given the values above:
5) Our answer is 2.25 g/mL (since mass is grams (g), and volume is milliliters (mL) in the problem above).
Answer:
251.33in²
Step-by-step explanation:
A cylindrical container contains some sand. If the diameter of the container is 10 inches and its height is 3 inches, about how much sand fits inside the container?
We solve the above question using the formula for Total surface area of a cylinder.
TSA = 2πr (h + r) Square units.
Where
h = Height of the cylinder
r = Radius of the cylinder
Diameter of the container is 10 inches
Hence, radius = Diameter/2 = 10/2 = 5 inches
Height is 3 inches.
Hence, Total surface area =
2 × π × 5 (5 + 3)
= 10π × (8)
= 251.32741229 in²
Approximately = 251.33 in²
Therefore, the amount of sand that can fit into the cylinder = 251.33 in²
Answer:
A
Step-by-step explanation:
4x/4=x
8/4=2
x=2
