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:
7.50 is the answer to the question
To apply a scale to a measure, you have to follow this rule:
Real measure x Scale = Scaled measure
So the drawings will have:
4 x 1/24 = 0'167 feet
6 x 1/24 = 0'25 feet
<span>Windows: 0'167 by 0'25 feet
</span>
<span>12 x 1/24 = 0'50 feet
</span><span>8 x 1/24 = 0'33 feet
</span>Doors: 0'33 by <span>0'50 feet</span>
