Write Newton’s formula used to approximate a solution of the equation x cubed minus x minus 20 equals 0 and find the third iteration value. Be sure to verify both parts of the answer are correct when making your selection.
a.) X subscript n plus 1 end subscript equals x subscript n minus fraction numerator x subscript n cubed minus x subscript n minus 20 over denominator 3 x subscript n squared minus 1 end fraction semicolon space x subscript 3 almost equal to 2.837138669
b.) X subscript n plus 1 end subscript equals 3 minus fraction numerator x subscript n cubed minus x subscript n minus 20 over denominator 3 x subscript n squared minus 1 end fraction semicolon space x subscript 3 almost equal to 2.854205773
c.) X subscript n plus 1 end subscript equals 3 plus fraction numerator x subscript n cubed minus x subscript n minus 20 over denominator 3 x subscript n squared minus 1 end fraction semicolon space x subscript 3 almost equal to 3.387645475
d.) X subscript n plus 1 end subscript equals x subscript n minus fraction numerator x subscript n cubed minus x subscript n minus 20 over denominator 3 x subscript n squared minus 1 end fraction semicolon space x subscript 3 almost equal to 3.2138370016