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Find the term independent of x in the ex...

Find the term independent of `x` in the expansion of `((3)/(2) x^(2) - (1)/(3x) )^(9)`.

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To find the term independent of \( x \) in the expansion of \( \left( \frac{3}{2} x^2 - \frac{1}{3x} \right)^9 \), we will follow these steps: ### Step 1: Identify the general term in the binomial expansion The general term \( T_{r+1} \) in the binomial expansion of \( (a + b)^n \) is given by: \[ T_{r+1} = \binom{n}{r} a^{n-r} b^r \] In our case, \( n = 9 \), \( a = \frac{3}{2} x^2 \), and \( b = -\frac{1}{3x} \). ### Step 2: Write the general term for our specific case Substituting the values into the formula, we get: \[ T_{r+1} = \binom{9}{r} \left( \frac{3}{2} x^2 \right)^{9-r} \left( -\frac{1}{3x} \right)^r \] ### Step 3: Simplify the general term Expanding this, we have: \[ T_{r+1} = \binom{9}{r} \left( \frac{3}{2} \right)^{9-r} (x^2)^{9-r} \left( -\frac{1}{3} \right)^r (x^{-1})^r \] This simplifies to: \[ T_{r+1} = \binom{9}{r} \left( \frac{3}{2} \right)^{9-r} \left( -\frac{1}{3} \right)^r x^{2(9-r) - r} \] \[ = \binom{9}{r} \left( \frac{3}{2} \right)^{9-r} \left( -\frac{1}{3} \right)^r x^{18 - 3r} \] ### Step 4: Find the term independent of \( x \) For the term to be independent of \( x \), the exponent of \( x \) must be zero: \[ 18 - 3r = 0 \] Solving for \( r \): \[ 3r = 18 \implies r = 6 \] ### Step 5: Substitute \( r \) back to find the specific term Now, we find the term \( T_{r+1} \) when \( r = 6 \): \[ T_{7} = \binom{9}{6} \left( \frac{3}{2} \right)^{3} \left( -\frac{1}{3} \right)^{6} \] ### Step 6: Calculate the binomial coefficient and powers Calculating \( \binom{9}{6} \): \[ \binom{9}{6} = \binom{9}{3} = \frac{9 \times 8 \times 7}{3 \times 2 \times 1} = 84 \] Calculating \( \left( \frac{3}{2} \right)^{3} \): \[ \left( \frac{3}{2} \right)^{3} = \frac{27}{8} \] Calculating \( \left( -\frac{1}{3} \right)^{6} \): \[ \left( -\frac{1}{3} \right)^{6} = \frac{1}{729} \] ### Step 7: Combine all parts to find the term Now substituting these values back: \[ T_{7} = 84 \cdot \frac{27}{8} \cdot \frac{1}{729} \] Calculating: \[ T_{7} = \frac{84 \cdot 27}{8 \cdot 729} \] \[ = \frac{2268}{5832} = \frac{7}{18} \] ### Final Answer The term independent of \( x \) in the expansion is: \[ \frac{7}{18} \]
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