x³ + 3x - 4 = x³ - x + 4x - 4

= x(x² - 1) + 4(x - 1)

= x(x + 1)(x - 1) + 4(x - 1)

= (x - 1) [ x(x + 1) + 4 ]

=(x - 1)(x² + x + 4)

\(x^3+3x-4\)

\(=\left(x^3-x^2\right)+\left(x^2-x\right)+\left(4x-4\right)\)

\(=\left(x-1\right)\left(x^2+x+4\right)\)

x^3+3x-4 = (x^3-1)+(3x-3)

= (x-1).(x^2+x+1)+3.(x-1) = (x-1).(x^2+x+1+3) = (x-1).(x^2+x+4)

k mk nha

[(x+2)(x+5)][(x+3)(x+4)] -24 = ( x\(^2\) + 7x + 10)( x\(^2\) + 7x + 12) -24

Đặt : x\(^2\) + 7x + 10 = a ta được:

a * (a+2) - 24 = a\(^2\) + 2a -24 = a\(^2\) + 2a +1 - 5\(^2\) = (a+1)\(^2\) - 5\(^2\)

= (a + 1 -5)( a + 1 +5)

= (a-4)(a+6)

thay a ta được:

(a-4)(a-6) = ( x\(^2\) + 7x + 10 - 4)( x\(^2\) + 7x + 10 - 6)

= (x\(^2\) + 7x + 6)(x\(^2\) + 7x +4)

= (x+1)(x+6)(x\(^2\) + 7x + 4)

NHA!

\((x+5)^2+4(x+5)(x-5)+4(x^2-10x+25)=0\\\Rightarrow(x+5)^2+4(x+5)(x-5)+4(x^2-2\cdot x\cdot5+5^2)=0\\\Rightarrow(x+5)^2+2\cdot(x+5)\cdot2(x-5)+4(x-5)^2=0\\\Rightarrow(x+5)^2+2\cdot(x+5)\cdot2(x-5)+[2(x-5)]^2=0\\\Rightarrow[(x+5)+2(x-5)]^2=0\\\Rightarrow(x+5+2x-10)^2=0\\\Rightarrow(3x-5)^2=0\\\Rightarrow3x-5=0\\\Rightarrow3x=5\\\Rightarrow x=\frac53\\\text{#}Toru\)

Sao đề là phân tích mà lại "= 0" vậy bạn?

Tôi làm tạm theo cách này nhé.

\(x^4-2x^2-114x-1295\)

\(=\frac{d}{dx}\left(x^4-2x^2-114x-1295\right)\)

\(=4x^3-4x-114-0\)

\(=4x^3-4x-114\)

Bạn Phương Lê Nhật ơi!!!!

Đây là Toán 8 bạn ạ

Bạn giải mk ko hiểu j cả

Giải cụ thể đc ko bạn ạ

\(\left(x+1\right)\left(x+2\right)\left(x+3\right)\left(x+4\right)-24\) (sửa đề)

\(=\left[\left(x+1\right)\left(x+4\right)\right].\left[\left(x+2\right).\left(x+3\right)\right]-24\)

\(=\left(x^2+5x+4\right)\left(x^2+5x+6\right)-24\)

Đặt \(y=x^2+5x+4\), thay vào đa thức, ta được:

\(y\left(y+2\right)-24\)

\(=y^2+2y-24\)

\(=\left(y^2+2y+1\right)-25\)

\(=\left(y+1\right)^2-5^2\)

\(=\left(y+1-5\right)\left(y+1+5\right)\)

\(=\left(y-4\right)\left(y+6\right)\)

\(=\left(x^2+5x+4-4\right)\left(x^2+5x+4+6\right)\)

\(=\left(x^2+5x\right)\left(x^2+5x+10\right)\)

\(=x\left(x+5\right)\left(x^2+5x+10\right)\)

      \(5x^2-7x+2\)

\(=5x^2-5x-2x+2\)

\(=5x\left(x-1\right)-2\left(x-1\right)\)

\(=\left(x-1\right)\left(5x-2\right)\)

\(5x^2-7x+2\)

\(=5x^2-5x-2x+2\)

\(=5x\left(x-1\right)-2\left(x-1\right)\)

\(=\left(5x-2\right)\left(x-1\right)\)

5x^2-7x + 2

= 5x^2 - 5x - 2x + 2 

= 5x( x - 1 ) - 2(x - 1)

= ( x - 1 ) (5x - 2)

\(1,\\ 1,=15\left(x+y\right)\\ 2,=4\left(2x-3y\right)\\ 3,=x\left(y-1\right)\\ 4,=2x\left(2x-3\right)\\ 2,\\ 1,=\left(x+y\right)\left(2-5a\right)\\ 2,=\left(x-5\right)\left(a^2-3\right)\\ 3,=\left(a-b\right)\left(4x+6xy\right)=2x\left(2+3y\right)\left(a-b\right)\\ 4,=\left(x-1\right)\left(3x+5\right)\\ 3,\\ A=13\left(87+12+1\right)=13\cdot100=1300\\ B=\left(x-3\right)\left(2x+y\right)=\left(13-3\right)\left(26+4\right)=10\cdot30=300\\ 4,\\ 1,\Rightarrow\left(x-5\right)\left(x-2\right)=0\Rightarrow\left[{}\begin{matrix}x=2\\x=5\end{matrix}\right.\\ 2,\Rightarrow\left(x-7\right)\left(x+2\right)=0\Rightarrow\left[{}\begin{matrix}x=7\\x=-2\end{matrix}\right.\\ 3,\Rightarrow\left(3x-1\right)\left(x-4\right)=0\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=4\end{matrix}\right.\\ 4,\Rightarrow\left(2x+3\right)\left(2x-1\right)=0\\ \Rightarrow\left[{}\begin{matrix}x=-\dfrac{3}{2}\\x=\dfrac{1}{2}\end{matrix}\right.\)