$x+1=12\left( 1-x \right)+2x$
Distribute $12$ through the parentheses$x+1=12-12x+2x$
Collect like terms$x+1=12-10x$
Move the variable to the left-hand side and change its sign$x+1+10x=12$
Move the constant to the right-hand side and change its sign$x+10x=12-1$
Collect like terms$11x=12-1$
Subtract the numbers$11x=11$
Divide both sides of the equation by $11$$x=1$