Answer:
see explanation
Step-by-step explanation:
Given A is directly proportional to r² then the equation relating them is
A = kr² ← k is the constant of proportion
To find k use the condition when r = 5, A = 75 , then
75 = k × 5² = 25k ( divide both sides by 25 )
3 = k
A = 3r² ← equation of proportion
(a)
when r = 4, then
A = 3 × 4² = 3 × 16 = 48
(b)
when A = 147 , then
147 = 3r² ( divide both sides by 3 )
49 = r² ( take the square root of both sides )
r =
= 7
Answer:
1/y+4
Step-by-step explanation:
1-5+1/y+8
1/y+(1-5+8)
1/y+4
Answer:
V(max) = 8712.07 in³
Dimensions:
x (side of the square base) = 16.33 in
girth = 65.32 in
height = 32.67 in
Step-by-step explanation:
Let
x = side of the square base
h = the height of the postal
Then according to problem statement we have:
girth = 4*x (perimeter of the base)
and
4* x + h = 98 (at the most) so h = 98 - 4x (1)
Then
V = x²*h
V = x²* ( 98 - 4x)
V(x) = 98*x² - 4x³
Taking dervatives (both menbers of the equation we have:
V´(x) = 196 x - 12 x² ⇒ V´(x) = 0
196x - 12x² = 0 first root of the equation x = 0
Then 196 -12x = 0 12x = 196 x = 196/12
x = 16,33 in ⇒ girth = 4 * (16.33) ⇒ girth = 65.32 in
and from equation (1)
y = 98 - 4x ⇒ y = 98 -4 (16,33)
y = 32.67 in
and maximun volume of a carton V is
V(max) = (16,33)²* 32,67
V(max) = 8712.07 in³
Answer:
they are the same
Step-by-step explanation:
Apply substitution
x+4(-2x-4)=19
x – 8x – 16 = 19
-7x = 19 + 16
-7x = 35
x = -5
Then substitute this value to the other equation
y=-2x-4
y = -2(-5) – 4
y = 10 – 4
y = 6
the answer is then letter A. (-5,6)