The value of the formula 3 * 1! - 4 * 2! + 5 * 3! - 6 * 4! + 7 * 5! - 8 * 6! + 9 * 7! Is () in steps
=(2+1)*1! -(3+1)*2! +(4+1)*3! -(5+1)*4! +(6+1)*5! -(7+1)*6! +(8+1) *7!
= (2! +1!) -(3!+2!) +(4!+3!) -(5!+4!) +(6!+5!) -(7!+6!) +(8!+7!)
= 1 +8!
= 40321
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