Answer
{3/2}
Work Step by Step
You will need to create two seperate equations.
x+4=7-x
x+4-4=7-4-x
x=3-x
x+x=3-x+x
2x=3
2x/2=3/2
x=3/2
and
x+4=-7+x
x+4-4=-7-4+x
x=-11+x
x-x=-11+x-x
0x=-11
no solution
The solution set is {3/2}.