Answer
x=-4
Work Step by Step
$12=11x-14x\rightarrow$ combine like terms
$12=-3x\rightarrow$ divide both sides by -3
$12\div-3=-3x\div-3\rightarrow$ simplify
$-4=x$
Check the soution by plugging in the value for x and determine whether the resulting equation is true.
$12=11(-4)-14(-4)\rightarrow$ simplify
$12=-44+56\rightarrow$ simplify
$12=12$
This is true so the solution is correct.