Rewrite the equation as -6.8+4.2d=14.2.
Move all terms not containing d to the right side of the equation.
Add 6.8 to both sides of the equation.
Add 14.2 and 6.8.
Divide each term by 4.2 and simplify.
Divide each term in 4.2d=21 by 4.2.
Cancel the common factor of 4.2.
Divide 21 by 4.2.
Solve for d 14.2=-6.8+4.2d