2x ³ – 7x ² -12x + 45 trên 3x ³ – 19x ² +33x -9 đây là rút gọn phân thức nhé, máy mk k viết dc phân số 30/06/2021 Bởi Genesis 2x ³ – 7x ² -12x + 45 trên 3x ³ – 19x ² +33x -9 đây là rút gọn phân thức nhé, máy mk k viết dc phân số
$\text{Tử số:}$ $\text{2x³-7x²-12x + 45}$ $\text{=2x³-6x²-x²+3x-15x+45}$ $\text{=2x²(x-3)-x(x-3)-15(x-3)}$ $\text{=(x-3)(2x²-x-15)}$ $\text{=(x-3)(2x²-6x+5x-15)}$ $\text{=(x-3)[2x(x-3)+5(x-3)]}$ $\text{=(x-3)(x-3)(2x+5)}$ $\text{=(x-3)²(2x+5)}$ $\text{Mẫu số:}$ $\text{3x³-19x²+33x-9}$ $\text{=3x³-9x²-10x²+30x+3x-9}$ $\text{=3x²(x-3)-10x(x-3)+3(x-3)}$ $\text{=(x-3)(3x²-10x+3)}$ $\text{=(x-3)(3x²-9x-x+3)}$ $\text{=(x-3)[3x(x-3)-(x-3)]}$ $\text{=(x-3)(x-3)(3x-1)}$ $\text{=(x-3)²(3x-1)}$ $\frac{2x³-7x²-12x + 45}{3x³-19x²+33x-9}$ =$\frac{(x-3)²(2x+5)}{(x-3)²(3x-1)}$ =$\frac{2x+5}{3x-1}$ Bình luận
`(2x^3-7x^2-12x+45)/(3x^3-19x^2+33x-9)` `=(2x^3-6x^2-x^2+3x-15x+45)/(3x^3-9x^2-10x^2+30x+3x-9)` `=[2x^2(x-3)-x(x-3)-15(x-3)]/[3x^2(x-3)-10x(x-3)+3(x-3)]` `=[(2x^2-x-15)(x-3)]/[(3x^2-10x+3)(x-3)]` `=[(2x+5)(x-3)(x-3)]/[(3x-1)(x-3)(x-3)]` `=(2x+5)/(3x-1)` Bình luận
$\text{Tử số:}$
$\text{2x³-7x²-12x + 45}$
$\text{=2x³-6x²-x²+3x-15x+45}$
$\text{=2x²(x-3)-x(x-3)-15(x-3)}$
$\text{=(x-3)(2x²-x-15)}$
$\text{=(x-3)(2x²-6x+5x-15)}$
$\text{=(x-3)[2x(x-3)+5(x-3)]}$
$\text{=(x-3)(x-3)(2x+5)}$
$\text{=(x-3)²(2x+5)}$
$\text{Mẫu số:}$
$\text{3x³-19x²+33x-9}$
$\text{=3x³-9x²-10x²+30x+3x-9}$
$\text{=3x²(x-3)-10x(x-3)+3(x-3)}$
$\text{=(x-3)(3x²-10x+3)}$
$\text{=(x-3)(3x²-9x-x+3)}$
$\text{=(x-3)[3x(x-3)-(x-3)]}$
$\text{=(x-3)(x-3)(3x-1)}$
$\text{=(x-3)²(3x-1)}$
$\frac{2x³-7x²-12x + 45}{3x³-19x²+33x-9}$
=$\frac{(x-3)²(2x+5)}{(x-3)²(3x-1)}$
=$\frac{2x+5}{3x-1}$
`(2x^3-7x^2-12x+45)/(3x^3-19x^2+33x-9)`
`=(2x^3-6x^2-x^2+3x-15x+45)/(3x^3-9x^2-10x^2+30x+3x-9)`
`=[2x^2(x-3)-x(x-3)-15(x-3)]/[3x^2(x-3)-10x(x-3)+3(x-3)]`
`=[(2x^2-x-15)(x-3)]/[(3x^2-10x+3)(x-3)]`
`=[(2x+5)(x-3)(x-3)]/[(3x-1)(x-3)(x-3)]`
`=(2x+5)/(3x-1)`