Answer:
x ≤ -18. I hope this helps
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
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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
Solution
To find out which expressions represent the difference of exactly
two expressions
a) 6(x+7) - 2
This can be simplified as
6x + 42 - 2
6x + 40
Clearly this does not represent difference of the two
expressions .
b) -2j
Clearly this represents a single expression , this does not represent
a difference of 2 expression .
c) 4f - 2g
Here we have 2 different expressions 4f and 2g
Difference of these 2 expressions are 4f - 2g
Hence , this option represent difference of exactly two
expression
d) 3xyz - 10
3xtz - 10 represnts a single expression
Here we have a single expression
Therefore it does not represent difference of exactly 2
expression .
Answer:
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Step-by-step explanation:
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