<span>1/3(21-3a)=6-a I simplified the equation to the form, which is simple to understand <span>1/3(21-3a)=6-a Simplifying: <span> + 0.333333333333*(21-3a)=6-a Reorder the terms in parentheses <span>+(+7-1a)=6-a Remove unnecessary parentheses <span>+7-1a=+6-a We move all terms containing a to the left and all other terms to the right. <span>-1a+1a=+6-7 We simplify left and right side of the equation. <span>a=-1 <span>0=-1 The left and right sides are not equal, therefore there is no solution. This equation is invalid Hope this helped
