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Solve for n : ((2n)!)/( 3!( 2n-3) !) ...

Solve for n :
` ((2n)!)/( 3!( 2n-3) !) : ( n!)/( 2!( n-2)!) = 44 : 3 `

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To solve the equation \[ \frac{(2n)!}{3!(2n-3)!} : \frac{n!}{2!(n-2)!} = \frac{44}{3}, \] we will start by rewriting the ratio as an equation: \[ \frac{(2n)!}{3!(2n-3)!} = \frac{44}{3} \cdot \frac{n!}{2!(n-2)!}. \] ### Step 1: Simplify the left-hand side The left-hand side can be simplified using the definition of combinations: \[ \frac{(2n)!}{3!(2n-3)!} = \binom{2n}{3}. \] So we rewrite the equation as: \[ \binom{2n}{3} = \frac{44}{3} \cdot \frac{n!}{2!(n-2)!}. \] ### Step 2: Simplify the right-hand side The right-hand side can also be simplified: \[ \frac{n!}{2!(n-2)!} = \binom{n}{2}. \] Thus, we can rewrite the equation as: \[ \binom{2n}{3} = \frac{44}{3} \cdot \binom{n}{2}. \] ### Step 3: Write out the combinations Now we can express the combinations explicitly: \[ \binom{2n}{3} = \frac{(2n)(2n-1)(2n-2)}{3!} = \frac{(2n)(2n-1)(2n-2)}{6}, \] and \[ \binom{n}{2} = \frac{n(n-1)}{2}. \] ### Step 4: Substitute back into the equation Substituting these into our equation gives: \[ \frac{(2n)(2n-1)(2n-2)}{6} = \frac{44}{3} \cdot \frac{n(n-1)}{2}. \] ### Step 5: Clear the fractions To eliminate the fractions, multiply both sides by 6: \[ (2n)(2n-1)(2n-2) = \frac{44 \cdot 6}{3} \cdot \frac{n(n-1)}{2}. \] Calculating the right side: \[ \frac{44 \cdot 6}{3} = 88. \] So the equation simplifies to: \[ (2n)(2n-1)(2n-2) = 88 \cdot \frac{n(n-1)}{2}. \] ### Step 6: Simplify further This simplifies to: \[ (2n)(2n-1)(2n-2) = 44n(n-1). \] ### Step 7: Expand both sides Expanding the left-hand side: \[ (2n)(2n-1)(2n-2) = 8n^3 - 12n^2 + 4n. \] The right-hand side is: \[ 44n^2 - 44n. \] ### Step 8: Set the equation to zero Setting both sides equal gives: \[ 8n^3 - 12n^2 + 4n - 44n^2 + 44n = 0. \] Combining like terms: \[ 8n^3 - 56n^2 + 48n = 0. \] ### Step 9: Factor out common terms Factoring out \(n\): \[ n(8n^2 - 56n + 48) = 0. \] This gives us one solution \(n = 0\). Now we solve the quadratic: \[ 8n^2 - 56n + 48 = 0. \] ### Step 10: Use the quadratic formula Using the quadratic formula \(n = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}\): \[ n = \frac{56 \pm \sqrt{(-56)^2 - 4 \cdot 8 \cdot 48}}{2 \cdot 8}. \] Calculating the discriminant: \[ 3136 - 1536 = 1600. \] So, \[ n = \frac{56 \pm 40}{16}. \] Calculating the two possible values: 1. \(n = \frac{96}{16} = 6\) 2. \(n = \frac{16}{16} = 1\) ### Final Answer Thus, the solutions for \(n\) are \(n = 6\) and \(n = 1\). ---
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