Toán Lớp 7: 1) 6x^3 – x^2 – 2x
2) x^4 – 53 x^2 y^2 + 196y^4
3) x^3 +4x^2 – 29 x + 24 (đề bài là phân tích đa thức thành nhân từ ạ
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Toán Lớp 7: 1) 6x^3 – x^2 – 2x
2) x^4 – 53 x^2 y^2 + 196y^4
3) x^3 +4x^2 – 29 x + 24 (đề bài là phân tích đa thức thành nhân từ ạ
Comments ( 1 )
$\text{1) 6x³ – x² – 2x}$
$\text{= x(6x² – x – 2)}$
$\text{= x(6x² – 4x + 3x – 2)}$
$\text{= x[2x(3x – 2) + (3x – 2)]}$
$\text{= x(3x – 2)(2x + 1)}$
$\text{2) $x^{4}$ – 53$x^{2}$$y^{2}$ + 196$y^{4}$}$
$\text{= $x^{4}$ – 49$x^{2}$$y^{2}$ – 4$x^{2}$$y^{2}$ + 196$y^{4}$}$
$\text{= x²(x² – 49y²) – 4y²(x² – 49y²)}$
$\text{= (x² – 4y²)(x² – 49y²)}$
$\text{= (x – 2y)(x + 2y)(x – 7y)(x + 7y)}$
$\text{3) x³ + 4x² – 29x + 24}$
$\text{= x³ – x² + 5x² – 5x – 24x + 24}$
$\text{= x²(x – 1) + 5x(x – 1) – 24(x – 1)}$
$\text{= (x² + 5x – 24)(x – 1)}$
$\text{= (x² + 8x – 3x – 24)(x – 1)}$
$\text{= [x(x + 8) – 3(x + 8)](x – 1)}$
$\text{= (x – 3)(x + 8)(x – 1)}$
$\textit{Ha1zzz}$