Instantaneous rate of change = S'(r) = 8πr
S'(8) = 8π(8) = 64π
Therefore, the instantaneoud rate of change of the <span>surface area with respect to the radius r at r = 8</span> is 64π
Answer:
candles = $400
matches = $20
Step-by-step explanation:
Let cost of candles = $c
Let cost of matches = $m
c = 20 m (20 times m)
c + m = 420
20m + m = 420
21 m = 420
m = 20
c = 20 (20) = 400
Answer:
The value of x is 
.
Step-by-step explanation:
It is given that the inverse variation equation is
..... (1)
The value of y is 4 and the value of k is 7.
Substitute y=4 and k=7 in equation (1).
Divide both sides by 4.
Therefore the value of x is .
Answer:
Step-by-step explanation:
-1/4x>8
x>8/(-1/4)
x>(8/1)(-4/1)
x>-32/1
x>-32
x<-32
The answer is D.
--------------------------
-3t+7>=9
-3t>=9-7
-3t>=2
t>=2/-3
t>=-2/3
t<=-2/3
The answer is A.
Answer:
12 inches
Step-by-step explanation:
Let b represent the base
h represents the height
area of the parallelogram = base * height = 216 square inches
From the question'
b = 18 + 3h
Slot in the value of b
216 = (18 + 3h) * h
expand
216 = 18h + 3h^2
subtract 216 from both sides
0 = 18h + 3h^2 - 216
rearrange
3h^2 + 18h - 216 = 0
divide through by 3
h^2 + 6h - 72 = 0
Now, lets solve!
h^2 + 6h - 12h - 72 = 0
h( h + 6 ) - 12(h + 6) = 0
(h - 12) (h + 6) = 0
h - 12 = 0
h = 12
and
h + 6 = 0
h = - 6
Taking the positive value of h
Hence, the height is 12 inches
Lets check
when h = 12 inches
Area of the parallelogram = 18* 12 = 216 square inches .... correct
when h = -6inches
A = 18 * -6 ≠ 216 square inches
So height is 12 inches
