1.44 per kg
take 1.3 x 2, then subtract 12.7, finally divide that by 7
Intersection of the first two lines:

Multiply the first equation by 4 and the second by 5:

Subtract the two equations:

Plug this value for y in one of the equation, for example the first:

So, the first point of intersection is 
We can find the intersection of the other two lines in the same way: we start with

Use the fact that x and y are the same to rewrite the second equation as

And since x and y are the same, the second point is 
So, we're looking for a line passing through
and
. We may use the formula to find the equation of a line knowing two of its points, but in this case it is very clear that both points have the same coordinates, so the line must be 
In the attached figure, line
is light green, line
is dark green, and their intersection is point A.
Simiarly, line
is red, line
is orange, and their intersection is B.
As you can see, the line connecting A and B is the red line itself.
Answer:
The standard equation of the sphere is 
Step-by-step explanation:
From the question, the end point are (3,-2,4) and (7,12,4)
Since we know the end points of the diameter, we can determine the center (midpoint of the two end points) of the sphere.
The midpoint can be calculated thus
Midpoint = 
Let the first endpoint be represented as
and the second endpoint be
.
Hence,
Midpoint = 
Midpoint = 
Midpoint = 
Midpoint = 
This is the center of the sphere.
Now, we will determine the distance (diameter) of the sphere
The distance is given by






This is the diameter
To find the radius, r
From 

∴ 
r = 
Now, we can write the standard equation of the sphere since we know the center and the radius
Center of the sphere is 
Radius of the sphere is 
The equation of a sphere of radius r and center
is given by

Hence, the equation of the sphere of radius
and center
is


This is the standard equation of the sphere
The volume is 336 cubic feet
6x8x3 = 144
8x4x6= 192
144+192=336