8. What should you do first in solving the equation 2d² +8d - 10 = 0 by completing the square? A. Check the values of the variable obtained by substituting each in the original equation. B. Divide both sides of the equation by the numerical coefficient of the quadratic term then simplify. C. Express the perfect square trinomial on the left side of the equation as a square of a binomial. D. Write the equation such that the terms with variables are on the left side of the​