## Intermediate Algebra (12th Edition)

Using the properties of equality, the given equation, $8x-(1-x)=3(1+3x)-4 ,$ is equivalent to \begin{array}{l}\require{cancel} 8x-1+x=3+9x-4 \\\\ 8x+x-9x=3-4+1 \\\\ 0=0 \text{ (TRUE)} .\end{array} Since the solution above ended with a TRUE statement, then the given equation is an identity. Hence, the solution is $\text{ the set of all real numbers }.$