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a) x3-4x2+x+6=x3-3x2-(x2-x-6) = x2(x-3) - (x-3)(x+2) = (x-3)(x2-x-2) = (x-3)(x-2)(x+1)
hình như câu b là x3 + 2x2 -x -2 đúng k. đặt nhân tử chung là ra thôi.
good luck
a) Nhẩm nghiệm nha. Ta được x=-1 thì x3 - 4x2 + x + 6=0 nên ta sẽ phân tích thành x+1 là nhân tử chung :
x3 - 4x2 + x + 6 = x3 +x2 - 5x2 - 5x + 6x + 6
= (x3 +x2 ) - (5x2 + 5x) + (6x +6)
= x2(x+1) - 5x(x+1) +6(x+1)
=(x+1)(x2 -5x+6)
=(x+1)(x2 - 2x - 3x + 6)
=(x+1)(x-2)(x-3)
Câu b bạn kiểm đề lại dùm mình nha
a/ \(x^3-5x^2+8x-4\)
= \(\left(x^3-x^2\right)-\left(4x^2-4x\right)+\left(4x-4\right)\)
= \(x^2\left(x-1\right)-4x\left(x-1\right)+4\left(x-1\right)\)
= \(\left(x-1\right)\left(x^2-4x+4\right)\)
= \(\left(x-1\right)\left(x-2\right)^2\)
b/ \(x^3-x^2+x-1\)
= \(\left(x^3-x^2\right)+\left(x-1\right)\)
= \(x^2\left(x-1\right)+\left(x-1\right)\)
= \(\left(x-1\right)\left(x^2+1\right)\)
\(\left(x^2+4x-3\right)^2-5x.\left(x^2+4x-3\right)+6x^2\)
\(=\left[\left(x^2+4x-3\right)^2-2.\left(x^2+4x-3\right).2,5x+\left(2,5x\right)^2\right]-\left(0,5x\right)^2\)
\(=\left(x^2+4x-3-2,5x\right)^2-\left(0,5x\right)^2\)
\(=\left(x^2+4x-3-2,5x-0,5x\right).\left(x^2-4x-3-2,5x+0,5x\right)\)
\(=\left(x^2+x-3\right).\left(x^2+2x-3\right)\)
Tham khảo nhé~
\(4x^3+4x^2+x-1\)
\(=4x^3+2x^2+2x^2+x-1\)
\(=2x^2.\left(2x+1\right)+x.\left(2x+1\right)-1\)
\(=\left(2x+1\right).\left(2x^2+x\right)-1\)
\(=x.\left(2x+1\right)^2-1\)
\(=\left[\sqrt{x}.\left(2x+1\right)\right]^2-1^2\)
\(=\left[\sqrt{x}.\left(2x+1\right)-1\right].\left[\sqrt{x}.\left(2x+1\right)+1\right]\)
Tham khảo nhé~
a, \(x^3+6x^2+11x+6\)
\(=x^3+3x^2+3x^2+9x+2x+6\)
\(=x^2\left(x+3\right)+3x\left(x+3\right)+2\left(x+3\right)\)
\(=\left(x+3\right)\left(x^2+3x+2\right)\)
\(=\left(x+3\right)\left(x^2+x+2x+2\right)\)
\(=\left(x+3\right)\text{[}x\left(x+1\right)+2\left(x+1\right)\text{]}\)
\(=\left(x+3\right)\left(x+1\right)\left(x+2\right)\)
b, \(2x^3+3x^2+3x+2\)
\(=2x^3+2x^2+x^2+x+2x+2\)
\(=2x^2\left(x+1\right)+x\left(x+1\right)+2\left(x+1\right)\)
\(=\left(x+1\right)\left(2x^2+x+2\right)\)
c, \(x^3-4x^2-8x+8\)
\(=x^3+2x^2-6x^2-12x+4x+8\)
\(=x^2\left(x+2\right)-6x\left(x+2\right)+4\left(x+2\right)\)
\(=\left(x+2\right)\left(x^2-6x+4\right)\)
4x3+4x4−x2−x
=4x3(x+1)−x(x+1)
=(x+1)(4x3−1)
ĐÂY NHÉ. T.I.C.K MÌNH VỚI
a
4x2--25=0
=> (2x)22 --52 =0
=> (2x-5)(2x+5)=0
\(\orbr{\begin{cases}2x-5=0\\2x+5=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}X=\frac{5}{2}\\X=\frac{-5\:\:. \:\:\:\:\:\:\:\:\:\:TT}{2}\end{cases}Mình\:}\)
\(4x^2=25\Rightarrow x^2=\frac{25}{4}\Rightarrow x=\sqrt{\frac{25}{4}}\) \(=\frac{5}{2}\)
\(\left(x^3-x^2\right)^2-\left(4x^2-8x+4\right)=0\)
= \(\left(x^3-x^2\right)^2-\left(2x-2\right)^2=0\)
=(\(\left(x^3-x^2-2x+2\right)\left(x^3-x^2+2x-2\right)=0\)
=\(\left[x^2\left(x-1\right)-2\left(x-1\right)\right]\) \(\left[x^2\left(x-1\right)+2\left(x-1\right)\right]\)=0
=\(\left(x-1\right)\left(x^2-2\right)\left(x-1\right)\left(x^2+2\right)\) = 0
= \(\left(x-1\right)\left(x^2-2\right)\left(x^2+2\right)=0\)
=\(\left(x-1\right)\left(x^4-4\right)\) = 0
=> \(x-1=0\) hoặc \(x^4-4=0\)
=> \(x=1\) hoặc \(x=\pm\sqrt{2}\)
câu 2
a)\(\left(3x^2\right)^3-\left(2x\right)^3\)
= \(\left(3x^2-2x\right)\left(9x^4-54x^5+36x^4-4x^2\right)\)
= \(x\left(3x-2\right)\left(9x^4-54x^5+36x^4-4x^2\right)\)
may be wrong , but chawsc k nhiều , chỗ nào k hiểu ib hỏi mk sai nha <3
\(x^3-4x^2+x+6\)
\(=x^3-2x^2-2x^2+4x-3x+6\)
\(=x^2\left(x-2\right)-2x\left(x-2\right)-3\left(x-2\right)\)
\(=\left(x^2-2x-3\right)\left(x-2\right)\)
\(=\left(x+1\right)\left(x-3\right)\left(x-2\right)\)
Chúc bạn học tốt.
x3 - 4x2 + x + 6
= x3 - 2x2 - 2x2 + 4x - 3x + 6
= x2(x - 2) - 2x(x - 2) - 3(x - 2)
= (x - 2)(x2 - 2x - 3)
= (x - 2)(x2 - 2x + 1 - 4)
= (x - 2)[(x - 1)2 - 4]
= (x - 2)(x - 1 - 2)(x - 1 + 2)
= (x - 2)(x - 3)(x + 1)