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For all x and y, (4x^2 – 6xy – 12y^2 ) – (8x^2 – 12xy + 4y^2 ) = ?
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Updated on: 26 May 2017, 12:08
Updated on: 26 May 2017, 12:08
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For all x and y, \((4x^2 – 6xy – 12y^2 ) – (8x^2 – 12xy + 4y^2 ) = ?\)
(A) \(–4x^2 – 18xy – 16y^2\)
(B) \(–4x^2 + 6xy – 16y^2\)
(C) \(–4x^2 + 6xy – 8y^2\)
(D) \(4x^2 – 6xy + 16y^2\)
(E) \(12x^2 – 18xy – 8y^2\)
(A) \(–4x^2 – 18xy – 16y^2\)
(B) \(–4x^2 + 6xy – 16y^2\)
(C) \(–4x^2 + 6xy – 8y^2\)
(D) \(4x^2 – 6xy + 16y^2\)
(E) \(12x^2 – 18xy – 8y^2\)
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Re: For all x and y, (4x^2 – 6xy – 12y^2 ) – (8x^2 – 12xy + 4y^2 ) = ?
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26 May 2017, 13:59
26 May 2017, 13:59
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Kritesh wrote:
For all x and y, \((4x^2 – 6xy – 12y^2 ) – (8x^2 – 12xy + 4y^2) = ?\)
(A) \(–4x^2 – 18xy – 16y^2\)
(B) \(–4x^2 + 6xy – 16y^2\)
(C) \(–4x^2 + 6xy – 8y^2\)
(D) \(4x^2 – 6xy + 16y^2\)
(E) \(12x^2 – 18xy – 8y^2\)
(A) \(–4x^2 – 18xy – 16y^2\)
(B) \(–4x^2 + 6xy – 16y^2\)
(C) \(–4x^2 + 6xy – 8y^2\)
(D) \(4x^2 – 6xy + 16y^2\)
(E) \(12x^2 – 18xy – 8y^2\)
This is all about collecting like terms
(4x² – 6xy – 12y²) – (8x² – 12xy + 4y²) = ??
4x² - 8x² = -4x²
–6xy - (–12xy) = 6xy (aka +6xy)
–12y² - 4y² = -16y²
So, (4x² – 6xy – 12y²) – (8x² – 12xy + 4y²) = -4x² + 6xy -16y²
Answer:
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Re: For all x and y, (4x^2 – 6xy – 12y^2 ) – (8x^2 – 12xy + 4y^2 ) = ?
[#permalink]
26 May 2017, 13:43
26 May 2017, 13:43
\((4x^2 – 6xy – 12y^2 ) – (8x^2 – 12xy + 4y^2 )\)
= \((4x^2 - 8x^2) + (– 6xy + 12xy) + (– 12y^2 - 4y^2 )\)
= \(–4x^2 + 6xy – 16y^2\)(Option B)
= \((4x^2 - 8x^2) + (– 6xy + 12xy) + (– 12y^2 - 4y^2 )\)
= \(–4x^2 + 6xy – 16y^2\)(Option B)
