Question

x+3(mod x)=10 find the value of x

Answer 1

x +3|x| = 10
when x is positive
x +3|+x|= 10
4 x= 10
x =2.5

When x is negative
-x + 3|-x | =10
-x+3x = 10
2x = 10
x = 5

Answer 2

if x is positive number then
x+3(x) = 10
4x = 10
x = 10/4
x = 5/2

if x is negative number then 
(-x)+3(x) = 10
2x = 10
x = 10/2
x = 5

so there exists two values for x in x+3(mod x) = 10
therefore x = { 5/2 , 5 }