BAI 1.phan tich cac da thuc sau thanh nhan tu:
a,2x^2-2xy-5x+5y
b,8x^2+4xy-2ax-ay
c,x^3-4x^2+4x
d,2xy-x^2-y^2+16
e,x^2-y^2-2yz-z^2
g,3a^2-6ab+3b^2-12c^2
BAI 2.tinh nhanh
a,37,5.8,5-7,5.3,4-6,6.7,5+1,5.37,5
b,35^2+40^2-25^2+80.35
BAI 3. Tim x biet:
a,x^3-1/9x=0
b,2x-2y-x^2+2xy-y^2=0
c,x(x-3)+x-3=0
d,x^2(x-3)+27-9x=0
BAI 4.Phan tich cac da thuc sau thanh nhan tu
a,x^2-4x+3
goi y :tach-4x=-x3xhoac tach3=-1+4
b,x^2+x-6
c,x^2-5x+6
d,x^4+4 (goi y:them va bot 4x^2)
BAI 5.Chung minh rang;
(3n+4)^2-16 chia het cho 3 voi moi so nguyen n.
BAI 6.Tinh gia tri cua bieu thuc sau:
M=a^3-a^2b-ab^2+b^3 voi a=5,75:b=4,25
BAI 7.Tim x biet:
a,x^2+x=6
b,6x^3+x^2=2x
Cho bieu thuc: \(Q=\left(\dfrac{x^2-2x}{2x^2+8}+\dfrac{2x^2}{x^2.\left(x-2\right)}\right).\left(\dfrac{x^2-x-2}{x^2}\right)\)
a, Rut gon bieu thuc Q
b, Tim gia tri ca x de Q co gia tri bang \(\dfrac{1}{4}\)
tim so tu nhien n de de gia tri bieu thuc A la so nguyen to a=n3-2n2+2n-1
Cho a,b,c là các cạnh tam giác. Chứng minh rằng:
a.\(a^3+b^3+c^3+2abc< a^2\left(b+c\right)+b^2\left(c+a\right)+c^2\left(a+b\right)\)
b.\(\left(a+b+c\right)^2\le9bc\) với \(a\le b\le c\)
c. \(2a^2b^2+2b^2c^2+2c^2a^2-a^4-b^4-c^4>0\)
d.\(4a^2b^2>\left(a^2+b^2-c^2\right)^2\)
tim so nguyen n de gia tri bieu thuc sau la so nguyen to: 3n3-5n2-+3n-5
Phân tích các đa thức sau thành nhân tử
a) \(\left(a+b+c\right)^2+\left(a+b-c\right)^2-4c^2\)
b) \(4a^2b^2-\left(a^2+b^2-c^2\right)^2\)
c) \(a^4+b^4+c^4-2a^2b^2-2b^2c^2-2a^2c^2\)
d) \(a\left(b^3-c^3\right)+b\left(c^3-a^3\right)+c\left(a^3-b^3\right)\)
phan tich da thuc thanh nhan tu:
a)(x2-9)2+12x(x-3)2
b)a(b2+c2)-b(c2+a2)+c(a2+b2)-2abc
c)(a+b+c)3-a3-b3-c3
Phan tich da thuc thanh nhan tu
M=\(a\left(b^2-c^2\right)+b\left(c^2-a^2\right)+c\left(a^2-b^2\right)\)
Phan tich da thuc thanh nhan tu
M=\(a\left(b^2-c^2\right)+b\left(c^2-a^2\right)+c\left(a^2-b^2\right)\)