I can't use K-Map's i only can use boolean algebra to solve these problems

This is an example of one of the many things i need to simplify using boolean algebra

D'C'B'A+D'C'BA'+D'C'BA+D'CBA'+D'CBA+DC'B'A'+DC'BA

Any kind of help is appreciated

use brain.

(i guess you already know: if you have the OR (+), then you can shift terms around)

look at terms that have 3 out of 4 the same
the first and the third term as example:

D'C'B'A + D'C'BA + ...
does it matter if B is 1 or 0? no, because those two cases have the same result and thus can be simplified to
D'C'A + ...