\(-7-5-x=12+\left(-5+8\right)\)
\(\Leftrightarrow-12-x=12+3\)
\(\Leftrightarrow-12-x=16\)
\(\Leftrightarrow x=-12-16\)
\(\Leftrightarrow x=-28\)
\(\text{Vậy }x=-28\)
-7-5-x=12+(-5+8)
-7-5-x=15
5-x=-7-15
5-x=-7+(-15)
5-x=-(7+15)
5-x=-22
x=5-(-22)
x=5+22
x=27
Vậy x=27