Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(=x^4+1999x^2-x+1999x+1999\)
\(=\left(x^4-x\right)+\left(1999x^2+1999x+1999\right)\)
\(=x\left(x^3-1\right)+1999\left(x^2+x+1\right)\)
\(=x\left(x-1\right)\left(x^2+x+1\right)+1999\left(x^2+x+1\right)\)
\(=\left(x^2+x+1\right)\left(x^2-x+1999\right)\)
x3 _ x2 _ 4x - 4 = 0
x mũ 2(x+1)- 4(x+1)=0
(x mũ 2 - 4) (x+1)=0
(x+2) (x-2) (x+1) =0
suy ra (x+2)=0
(x-2)=0
(x+1)=0
vậy x=-2
x=2
x= -1
good luck!
Sửa đề : \(x^3-x^2-4x+4=0\)
\(\Leftrightarrow x^2\left(x-1\right)-4\left(x-1\right)=0\)
\(\Leftrightarrow\left(x^2-4\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left(x-2\right)\left(x+2\right)\left(x-1\right)=0\Leftrightarrow x=\pm2;1\)
a) \(x^4+x^3+x+1\)
\(\left(x^4+x^3\right)+\left(x+1\right)\)
\(x^3\left(x+1\right)\)+(x+1)
(x+1)(\(x^3+1\))
e)\(ax^2+ay-bx^2-by\)
\(\left(ax^2+ay\right)-\left(bx^2+by\right)\)
\(a\left(x^2+y\right)-b\left(x^2+y\right)\)
\(\left(x^2+y\right)\left(a-b\right)\)
\(A=x^4+2000x^2+1999x+2000=\left(x^2-x+2000\right)\left(x^2+x+1\right)\)\(A=\left(x^2+x-1\right)^2+1999\left(x^2+x+1\right)+1\)
1) =\(x^7-x+x^2+x\)+1
=\(x\left(x^6-1\right)+\left(x^2+x+1\right)\)
=\(x\left(x^3-1\right)\left(x^3+1\right)\)\(+\left(x^2+x+1\right)\)
=x(x^3+1)(x-1)(x^2+x+1)+(x^2+x+1)
=[(x^4+x)(x-1)+1](x^2+x+1)
=(x^5-x^4+x^2-x)(x^2+x+1)
Trả lời:
1, x7 + x2 + 1
= x7 + x2 + 1 + x6 - x6 + x5 - x5 + x4 - x4 + x3 - x3 + x2 - x2 + x - x
= ( x7 + x6 + x5 ) - ( x6 + x5 + x4 ) + ( x4 + x3 + x2 ) - ( x3 + x2 + x ) + ( x2 + x + 1 )
= x5 ( x2 + x + 1 ) - x4 ( x2 + x + 1 ) + x2 ( x2 + x + 1 ) - x ( x2 + x + 1 ) + ( x2 + x + 1 )
= ( x2 + x + 1 )( x5 - x4 + x2 - x + 1 )
b, x8 + x7 + 1
= x8 + x7 + 1 + x6 - x6 + x5 - x5 + x4 - x4 + x3 - x3 + x2 - x2 + x - x
= ( x8 + x7 + x6 ) - ( x6 + x5 + x4 ) + ( x5 + x4 + x3 ) - ( x3 + x2 + x ) + ( x2 + x + 1 )
= x6 ( x2 + x + 1 ) - x4 ( x2 + x + 1 ) + x3 ( x2 + x + 1 ) - x ( x2 + x + 1 ) + ( x2 + x + 1 )
= ( x2 + x + 1 )( x6 - x4 + x3 - x + 1 )
x + x2 - x3 - x4 = 0
x.(1+x) - x3.(1+x) = 0
x.(1+x).(1-x2) = 0
x.(1+x).(12 -x2) = 0
x.(1+x).(1+x).(1-x) = 0
x.(1+x)2.(1-x) = 0
=> x = 0
(1+x)2 = 0 => 1 + x =0 => x = -1
1-x = 0 => x = 1
KL:...
\(\left(x^2+2\right)^2-\left(x+2\right)\left(x-2\right)\left(x^2+4\right)\)
\(=x^4+4x^2+4-\left(x^2-4\right)\left(x^2+4\right)\)
\(=x^4+4x^2+4-x^4+16=4x^2+20=4\left(x^2+5\right)\)
A= x4 +y4 = (x4 +2x2.y2 +y4) - 2 (xy)2 = (x2 +y2)2 - 2(xy)2 = 152 - 2.62 = 225 - 72 =153
\(\left(x+1\right)^2=4\left(x^2-2x+1\right)^2\)
\(\Leftrightarrow\left(x+1\right)^2-4\left(x^2-2x+1\right)^2=0\)
\(\Leftrightarrow\left(x+1\right)-\left(2x^2-4x+2\right)^2=0\)
\(\Leftrightarrow\left(x+1-2x^2+4x-2\right)\left(x+1+2x^2-4x+2\right)=0\)
\(\Leftrightarrow\left(-2x^2+5x-1\right)\left(2x^2-3x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}-2x^2+5x-1=0\\2x^2-3x+3=0\left(loai\right)\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{5+\sqrt{17}}{4}\\x=\dfrac{5-\sqrt{17}}{4}\end{matrix}\right.\)
1)x4+1999x2−1998x+1999.1)x4+1999x2-1998x+1999.
=x4+1999x2+x−1999x+1999=x4+1999x2+x-1999x+1999
=(x4+x)+(1999x2−1999x+1999)=(x4+x)+(1999x2-1999x+1999)
=x(x3+1)+1999(x2−x+1)=x(x3+1)+1999(x2-x+1)
=x(x+1)(x2−x+1)+1999(x2−x+1)=x(x+1)(x2-x+1)+1999(x2-x+1)
=(x2−x+1)[x(x+1)+1999]=(x2-x+1)[x(x+1)+1999]
=(x2−x+1)(x2+x+1999).=(x2-x+1)(x2+x+1999).
# Chúc bạn học tốt!
Cảm ơn nhìu nhá...:)))