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:
7.74 square cm
Step-by-step explanation:
To find the leftovers, calculate the area of the square and the area of the circle. Then subtract the two.
Square: A = s*s = 6*6 = 36
Circle: 
The area leftover is A = 36 - 28.26 = 7.74
18
First you want to change the 20% into a decimal which is .20
Next you want to multiply 90 by .20 because that will give you the answer for 20% of 90
90x.20=18
Hope that helps
Answer: The answer is C, 4 to the 21st over 5 to the 6th power.
