Question

7/x+35=10

Answer 1

7/x+35 = 10

7/x = -25
x = -7/25

Answer 2

The way you typed it:

7/x = -25
-25x = 7
x = -7/25

if you meant:
7/(x+35) = 10
then
10x + 350 = 7
10x = -343
x = -343/10