Inverse Deltas of an Array Your task is to, given an array of signed 32 bit integers, recompile it with its inverse deltas. For example, the list
1  3  4  2  8

holds the deltas:
  2  1 -2  6

which are then negated, yielding:
 -2 -1  2 -6

and recompiled, yielding:
1 -1 -2  0 -6

as the final result.
Input/Output
You will be given a list/array/table/tuple/stack/etc. of signed integers as input through any standard input method.
You must output the modified data once again in any acceptable form, following the above delta inversion method.
You will receive N inputs where 0 &lt; N &lt; 10 where each number falls within the range -1000 &lt; X &lt; 1000
Test Cases
5 6 7 8          -&gt; 5 4 3 2
1 3 4 2 8        -&gt; 1 -1 -2 0 -6
32 18 25 192 199 -&gt; 32 46 39 -128 -135

Notes

You are not restricted to the delta based method: if you can work out the easier method (which shouldn't be too hard), you're free to use it.
As stated in above, you will always receive at least 1 input, and no more than 9.
The first number of the output must always be the first number of the input, if this is not the case, your method is incorrect.
Only Standard Input Output is accepted
Standard loopholes apply
This is code-golf, so the lowest byte-count wins!
Have fun!

We have a winner.
Dennis's Jelly Answer at a Tiny 3 Bytes has taken home the gold, due to the fact that I am under the impression it cannot be beaten.
I was mildly disappointed I didn't get to see an answer based on the original spec, however, I may later put a bounty on precisely that.
Jelly, 7 3 bytes
ḤḢ_

Try it online!
Background
The deltas of (a, b, c, d) are b - a, c - b, and d - c. Cumulatively reducing (a, b - a, c - b, d - c) by subtraction yields a - (b - a) = 2a - b, 2a - b - (c - b) = 2a - c, and 2a - c - (d - c) = 2a - d, so the correct result is (2a - a, 2a - b, 2a - c, 2a - d).
How it works
ḤḢ_  Main link. Argument: A (array)

Ḥ    Unhalve; multiply all integers in A by 2.
 Ḣ   Head; extract first element of 2A.
  _  Subtract the elements of A from the result.