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What is |{:(-a^(2),ab,ac),(ab,-b^(2),bc)...

What is `|{:(-a^(2),ab,ac),(ab,-b^(2),bc),(ac,bc,-c^(2)):}|` equal to ?

A

4 abc

B

`4a^(2)bc`

C

`4a^(2)b^(2)c^(2)`

D

`-4a^(2)b^(2)c^(2)`

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The correct Answer is:
To find the value of the determinant \[ D = \begin{vmatrix} -a^2 & ab & ac \\ ab & -b^2 & bc \\ ac & bc & -c^2 \end{vmatrix} \] we can simplify the calculation by factoring out common terms from each row. ### Step 1: Factor out common terms from each row From the first row, we can factor out \(-a\), from the second row, we can factor out \(-b\), and from the third row, we can factor out \(-c\): \[ D = (-a)(-b)(-c) \begin{vmatrix} a & b & c \\ b & b & c \\ c & c & c \end{vmatrix} \] This gives us: \[ D = -abc \begin{vmatrix} a & b & c \\ b & -b & c \\ c & c & -c \end{vmatrix} \] ### Step 2: Calculate the determinant of the simplified matrix Now we need to calculate the determinant: \[ \begin{vmatrix} a & b & c \\ b & -b & c \\ c & c & -c \end{vmatrix} \] Using the determinant formula, we can expand this determinant: \[ = a \begin{vmatrix} -b & c \\ c & -c \end{vmatrix} - b \begin{vmatrix} b & c \\ c & -c \end{vmatrix} + c \begin{vmatrix} b & -b \\ c & c \end{vmatrix} \] ### Step 3: Calculate the 2x2 determinants 1. For the first determinant: \[ \begin{vmatrix} -b & c \\ c & -c \end{vmatrix} = (-b)(-c) - (c)(c) = bc - c^2 = c(b - c) \] 2. For the second determinant: \[ \begin{vmatrix} b & c \\ c & -c \end{vmatrix} = (b)(-c) - (c)(c) = -bc - c^2 = -bc - c^2 \] 3. For the third determinant: \[ \begin{vmatrix} b & -b \\ c & c \end{vmatrix} = (b)(c) - (-b)(c) = bc + bc = 2bc \] ### Step 4: Substitute back into the determinant equation Now substituting these back into our determinant equation: \[ D = a[c(b - c)] - b[-(bc + c^2)] + c[2bc] \] This simplifies to: \[ D = ac(b - c) + b(bc + c^2) + 2bc^2 \] ### Step 5: Combine like terms Now we can combine the terms: \[ D = acb - ac^2 + b^2c + bc^2 + 2bc^2 \] This can be simplified further: \[ D = acb - ac^2 + b^2c + 3bc^2 \] ### Final Result Thus, the value of the determinant is: \[ D = -abc(a + b + c) \]

To find the value of the determinant \[ D = \begin{vmatrix} -a^2 & ab & ac \\ ab & -b^2 & bc \\ ac & bc & -c^2 \end{vmatrix} ...
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