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
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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:
Yes math is hard.
Step-by-step explanation:
Math includes a bunch of equations and mumbo-jumbo.
Answer:
23/24
Step-by-step explanation:
To find the sum you must ad.
Fractions can only be added and subtracted when the denominators (the bottom numbers) are the same.
24 is the smallest number that 2, 3 and 8 go into.
1/2 = 12/24, 1/3 = 8/24, 1/8 = 3/24
23/24
No she can't spend $4.39 for each sandwich because if you divide 20 by 5 your quotient will be 4.
Answer:
120000000000000000
Step-by-step explanation:
1.2*10^17
