Answer:
its b
Step-by-step explanation:
Answer:
Length = 4cm
Width = 4cm
Height = 8cm
Step-by-step explanation:
The volume of the box = 128cm^3
LWH = Volume
LWH = 128cm^3
The side of the box = $1 per cm^2
The top and bottom of the box = $2 per cm^2
Let C be the cost function
C(LWH) = (1) 2H (L+W) + (2) 2LW
from LWH = 128cm^39
H = 128/LW
put H = 128/LW in equation for C(LWH)
C(LW) = (1) 2(128/LW) + (L+W) +(2) 2LW
= 256/LW(L+W) + 4LW
= 256(1/L + 1/W) + 4LW
Differentiate C with respect to L
dC/dL = 4W - 256/L^2 = 0
Differentiate C with respect to W
dC/dW = 4L - 256/W^2 = 0
The cost is minimum when the two partial derivatives equal 0
From 4W - 256/L^2 = 0
4W = 256/L^2
W = (256/L^2) 1/4
W = 64/L^2
From 4L - 256/W^2 = 0
4L = 256/W^2
L = (256/W^2) 1/4
L = 64/W^2
Since L = W,
L= W = cuberoot (64)
L = W = 4cm
Recall that H= 128/LW
H = 128/(4*4)
H= 128/16
H= 8cm
therefore;
L= 4cm
B= 4cm
H= 8cm
-4y = - 7x + 8
y = 7/4 x + 2
Answer:
x=-5
y=-2
Step-by-step explanation:
equation 1 - equation 2
(2x-4y=-2) - (2x+3y=-16) = (-7y=14)
y=14/-7=-2
then substitute y=-2 into any equation
2x-4(-2)=-2
2x+8=-2
2x=-10
x=-10/2=-5
