Question 62225
This one had a sinking 2, I don't know what you meant so I thought maybe you hit enter before you hit 2.  If I'm wrong let me know and I'll correct it.
1-x=72
-1+1-x=72-1
0-x=71
-x=71
-x/-1=71/-1
{{{highlight(x=-71)}}}
Check, if x=-71 does the equation balance?
1-(-71)=72
1+71=72
72=72  We're right, if I interpretted your question right.
Happy Calculating!!!