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If (x + y + z) = 12, xy + yz + zx = 44...

If ` (x + y + z) = 12, xy + yz + zx = 44 " and " xyz = 48`, then what is the value of `x^(3) + y^(3) + z^(3) `?

A

`104`

B

`144`

C

`196`

D

`288`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to find the value of \( x^3 + y^3 + z^3 \) given the equations: 1. \( x + y + z = 12 \) 2. \( xy + yz + zx = 44 \) 3. \( xyz = 48 \) We can use the identity that relates the sum of cubes to the sums and products of the variables: \[ x^3 + y^3 + z^3 - 3xyz = (x + y + z) \left( (x + y + z)^2 - 3(xy + yz + zx) \right) \] ### Step 1: Calculate \( (x + y + z)^2 \) Using the first equation: \[ (x + y + z)^2 = 12^2 = 144 \] ### Step 2: Substitute into the identity Now, we can substitute \( (x + y + z)^2 \) and \( xy + yz + zx \) into the identity: \[ x^3 + y^3 + z^3 - 3xyz = (x + y + z) \left( (x + y + z)^2 - 3(xy + yz + zx) \right) \] Substituting the values we have: \[ x^3 + y^3 + z^3 - 3(48) = 12 \left( 144 - 3(44) \right) \] ### Step 3: Calculate \( 3(xy + yz + zx) \) Calculating \( 3(44) \): \[ 3(44) = 132 \] ### Step 4: Substitute and simplify Now substitute this back into the equation: \[ x^3 + y^3 + z^3 - 144 = 12(144 - 132) \] Calculating \( 144 - 132 \): \[ 144 - 132 = 12 \] Now substitute this back into the equation: \[ x^3 + y^3 + z^3 - 144 = 12 \times 12 \] Calculating \( 12 \times 12 \): \[ 12 \times 12 = 144 \] ### Step 5: Solve for \( x^3 + y^3 + z^3 \) Now we have: \[ x^3 + y^3 + z^3 - 144 = 144 \] Adding 144 to both sides: \[ x^3 + y^3 + z^3 = 144 + 144 = 288 \] Thus, the value of \( x^3 + y^3 + z^3 \) is \( 288 \). ### Final Answer \[ \boxed{288} \]
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