6+3(4x+3)=-3(1-7x)

Solution for 6+3(4x+3)=-3(1-7x) equation:

6+3(4x+3)=-3(1-7x)

We simplify the equation to the form, which is simple to understand 
6+3(4x+3)=-3(1-7x)

Reorder the terms in parentheses
6+(+12x+9)=-3*(1-7x)

Remove unnecessary parentheses
+6+12x+9=-3+*(+1-7x+)

Reorder the terms in parentheses
6+12x+9=+(-3+21x)

Remove unnecessary parentheses
+6+12x+9=-3+21x

We move all terms containing x to the left and all other terms to the right. 
+12x-21x=-3-6-9

We simplify left and right side of the equation. 
-9x=-18

We divide both sides of the equation by -9 to get x. 
x=2