Bài 2: Nhân Đa Thức Với Đa Thức
<span data-v-a7c68f28="">Hướng dẫn giải Bài 8 (Trang 8 SGK Toán Đại số 8, Tập 1)</span>
<p><strong>L&agrave;m t&iacute;nh nh&acirc;n:</strong></p> <p><strong><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>)</mo><mo>&#160;</mo><mfenced><mrow><msup><mi>x</mi><mn>2</mn></msup><msup><mi>y</mi><mn>2</mn></msup><mo>-</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mi>x</mi><mi>y</mi><mo>+</mo><mn>2</mn><mi>y</mi></mrow></mfenced><mfenced><mrow><mi>x</mi><mo>-</mo><mn>2</mn><mi>y</mi></mrow></mfenced></math></strong></p> <p><strong><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>b</mi><mo>)</mo><mo>&#160;</mo><mfenced><mrow><msup><mi>x</mi><mn>2</mn></msup><mo>-</mo><mi>x</mi><mi>y</mi><mo>+</mo><msup><mi>y</mi><mn>2</mn></msup></mrow></mfenced><mfenced><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mfenced></math></strong></p> <p><strong>Giải:</strong></p> <p><strong><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>a</mi><mo>)</mo><mo>&#160;</mo><mfenced><mrow><msup><mi>x</mi><mn>2</mn></msup><msup><mi>y</mi><mn>2</mn></msup><mo>-</mo><mfrac><mn>1</mn><mn>2</mn></mfrac><mi>x</mi><mi>y</mi><mo>+</mo><mn>2</mn><mi>y</mi></mrow></mfenced><mfenced><mrow><mi>x</mi><mo>-</mo><mn>2</mn><mi>y</mi></mrow></mfenced><mspace linebreak="newline"/><mo>=</mo><msup><mi>x</mi><mn>2</mn></msup><msup><mi>y</mi><mn>2</mn></msup><mi>x</mi><mo>+</mo><msup><mi>x</mi><mn>2</mn></msup><msup><mi>y</mi><mn>2</mn></msup><mfenced><mrow><mo>-</mo><mn>2</mn><mi>y</mi></mrow></mfenced><mo>-</mo><mi>x</mi><mi>y</mi><mo>.</mo><mi>x</mi><mo>-</mo><mi>x</mi><mi>y</mi><mfenced><mrow><mo>-</mo><mn>2</mn><mi>y</mi></mrow></mfenced><mo>+</mo><mn>2</mn><mi>y</mi><mo>.</mo><mi>x</mi><mo>+</mo><mn>2</mn><mi>y</mi><mo>.</mo><mfenced><mrow><mo>-</mo><mn>2</mn><mi>y</mi></mrow></mfenced><mspace linebreak="newline"/><mo>=</mo><msup><mi>x</mi><mn>3</mn></msup><msup><mi>y</mi><mn>2</mn></msup><mo>-</mo><mn>2</mn><msup><mi>x</mi><mn>2</mn></msup><msup><mi>y</mi><mn>3</mn></msup><mo>-</mo><msup><mi>x</mi><mn>2</mn></msup><mi>y</mi><mo>+</mo><mn>2</mn><mi>x</mi><msup><mi>y</mi><mn>2</mn></msup><mo>+</mo><mn>2</mn><mi>x</mi><mi>y</mi><mo>-</mo><mn>4</mn><msup><mi>y</mi><mn>2</mn></msup></math></strong></p> <p><strong><math xmlns="http://www.w3.org/1998/Math/MathML"><mi>b</mi><mo>)</mo><mo>&#160;</mo><mfenced><mrow><msup><mi>x</mi><mn>2</mn></msup><mo>-</mo><mi>x</mi><mi>y</mi><mo>+</mo><msup><mi>y</mi><mn>2</mn></msup></mrow></mfenced><mfenced><mrow><mi>x</mi><mo>+</mo><mi>y</mi></mrow></mfenced><mspace linebreak="newline"/><mo>=</mo><msup><mi>x</mi><mn>2</mn></msup><mo>.</mo><mi>x</mi><mo>+</mo><msup><mi>x</mi><mn>2</mn></msup><mo>.</mo><mi>y</mi><mo>+</mo><mfenced><mrow><mo>-</mo><mi>x</mi><mi>y</mi></mrow></mfenced><mo>.</mo><mi>x</mi><mo>+</mo><mfenced><mrow><mo>-</mo><mi>x</mi><mi>y</mi></mrow></mfenced><mo>.</mo><mi>y</mi><mo>+</mo><msup><mi>y</mi><mn>2</mn></msup><mo>.</mo><mi>x</mi><mo>+</mo><msup><mi>y</mi><mn>2</mn></msup><mo>.</mo><mi>y</mi><mspace linebreak="newline"/><mo>=</mo><msup><mi>x</mi><mn>3</mn></msup><mo>+</mo><msup><mi>x</mi><mn>2</mn></msup><mo>.</mo><mi>y</mi><mo>-</mo><msup><mi>x</mi><mn>2</mn></msup><mo>.</mo><mi>y</mi><mo>-</mo><mi>x</mi><msup><mi>y</mi><mn>2</mn></msup><mo>+</mo><mi>x</mi><msup><mi>y</mi><mn>2</mn></msup><mo>+</mo><msup><mi>y</mi><mn>3</mn></msup><mspace linebreak="newline"/><mo>=</mo><msup><mi>x</mi><mn>3</mn></msup><mo>-</mo><msup><mi>y</mi><mn>3</mn></msup></math></strong></p>
Hướng dẫn Giải Bài 8 (Trang 8, SGK Toán 8, Tập 1)
GV: GV colearn
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Hướng dẫn Giải Bài 8 (Trang 8, SGK Toán 8, Tập 1)
GV: GV colearn