Substitute the values of the variables into the expression and then use the order of operations to evaluate the expression. Since a=1/3, b=9, and c=5 then:
[tex]12a+c-b=12(\frac{1}{3})+(5)-(9)[/tex]The first step to simplify an expression that does not involve expressions inside parenthesis and/or roots and powers, is to solve multiplications first. Multiply 12 times 1/3:
[tex]12(\frac{1}{3})+5-9=\frac{12}{3}+5-9=4+5-9[/tex]Then, solve for additions and substractions from left to right:
[tex]4+5-9=9-9=0[/tex]Therefore, for the given values of the variables:
[tex]12a+c-b=12(\frac{1}{3})+5-9=0[/tex]