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
X=15
expand the brackets and collect like terms so 6x+15=7x
then -6x to get x=15
Answer:
Answer is 1
Explanation:
(-6 + 5) / (-2 + 1)
-1 / -1
1
Answer:1968ft^2
Step-by-step explanation:
Perimeter(p)=178feet
P=2L+2w
178=2L+2w
178=2(L+w)
L+w=178 ➗ 2
L+w=89.............(1)
W+7=L
L-w=7...................(11)
L+w=89... ..........(1)
L-w=7...................(11)
Subtract (11) from (1)
2w=89-7
2w=82
w=82 ➗ 2
w=41 width=41feet
Substitute w=41 in (11)
L-w=7
L-41=7
L=7+41
L=48feet
Area= length x width
Area=48 x 41
Area=1968ft^2
