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:
c
Step-by-step explanation:
Answer:
26 2/3 minutes: The two boys meet after 26 2/3 minutes
Step-by-step explanation:
Distance covered by Jim = Distance covered by Bob
(5 mph)(t) = (8 mph)(t - 10)
Simplify this by performing the indicated multiplication:
(5 mph)(t) = (8 mph)(t) - 80 mi
or:
80 mi = (3 mph)(t), or
80 mi
t = ----------- = 26 2/3 minutes
3 mph
Answer:
the answer that 9-(2,4)
Step-by-step explanation:
