Answer
identity;
the set of all real numbers
Work Step by Step
Using the properties of equality, the given equation, $
10x-3(2x-4)=4(x+3)
,$ is equivalent to
\begin{array}{l}\require{cancel}
10x-6x+12=4x+12
\\\\
10x-6x-4x=12-12
\\\\
0=0
.\end{array}
Since the solution above ended with a TRUE statement, then the given equation is an identity. The solution is $\text{
the set of all real numbers
}.$