If there is such a scalar function <em>f</em>, then



Integrate both sides of the first equation with respect to <em>x</em> :

Differentiate both sides with respect to <em>y</em> :


Integrate both sides with respect to <em>y</em> :

Plug this into the equation above with <em>f</em> , then differentiate both sides with respect to <em>z</em> :



Integrate both sides with respect to <em>z</em> :

So we end up with

First, list the numbers from smallest to greatest:
12, 15, 18, 20, 23, 23, 28
Median is the middle number of the list—20.
the given expression is :
2(4√16x) - 2(4√2y) + 34√81x - 4(4√32y)
⇒ 8(√16x) - 8(√2y) + 34√81x - 16√32y
⇒8×4√x - 8√2y + 34×9√x - 16√16×2y [∵ √16 = 4 and √81 = 9]
⇒32√x - 8√2y + 306√x - 16×4√2y
⇒(32√x + 306√x) - 8√2y - 16×4√2y
⇒338√x -72√2y
Its not possible because if you try to multiply back and forth it wont work.