If x is one part of 35 then, the other part is _? .
Please answer my question fast.

Dear Student,
In the asked question it says "x is one part of 35", which means "x" is subtracted from 35. 
 
For other part of 35:

let other part be "y"
so, $x+y=35$
$\to y = 35-x$ 

ANSWER: other part of 35 is 35-x .

Regards.