áp dụng
(a^3+b^3)=(a+b)[(a+b)^2-3ab]
A=(x+1/x)[(x+1/x)^2-3]=3.(9-3)=3.6=18
Bạn ngonhuminh đáng lẽ kết quả là 24 chứ
1) Cho bieu thuc A=\(3+\frac{2}{x-1}\). Tinh gia tri cua bieu thuc A khi |2x-3|=1
2) Rut gon bieu thuc B=\(\frac{x}{x-1}\)-\(\frac{x-5}{x+1}\)-\(\frac{3-x}{1-x^2}\)
3) Tim cac gia tri nguyen cua x de bieu thuc \(\frac{B}{A}\)co gia tri nguyen duong
1.cho bieu thuc A=\(\left(\frac{2}{x-2}+\frac{1}{x+2}\right):\frac{1}{x+2}\)
a.rút gọn bieu thuc A
b.tinh gia tri cua A tại x,biet x=1
2.tim x nguyen de gia tri cua bieu thuc A nguyen
a.\(A=\frac{3}{x+2}\)
b.\(A=\frac{x+3}{x-2}\)
cau 1: tinh gia tri cua x thoa man
\(\left(x-3\right)\left(x^2+3x+9\right)+x\left(x+2\sqrt{2}\right)\left(2\sqrt{2}-x\right)=-3\)
cau 2.tinh GTLN cua bieu thuc
\(2x-2x^2+13\)
cau 3. tinh gia tri cua bieu thuc
\(\frac{3^{\left(x+y\right)^2}}{3^{\left(x-y\right)^2}}\)voi xy=\(\frac{1}{2}\)
cau 4. tim GTLN cua
\(-3x^2-6x-4\)
cau 5. cho ham so : f(x)=\(\frac{1}{5x+9}\)
tinh gia tri cua \(f\left(\frac{40}{25}\right)\)
cau 6. cho hinh thang can ABCD . Day nho AB,goc D bang 64 do. tinh so do goc ngoai tai A
cho bieu thuc \(Q=\frac{12x-15}{x^2-7x+12}-\frac{x+5}{x-4}+\frac{2x-3}{3-x}\) . Tim x de gia tri cua Q nguyen
1. tích các nghiệm cua phương trình(x-2009)(x-2008)(x-2007)...(x-1)x(x+1)...(x+2010)=0
2.cho abc=2008 . khi do gia tri cua bieu thuc
\(\frac{2008a}{\left(ab+2008a+2008\right)}+\frac{b}{bc+b+2008}+\frac{c}{ac+c+1}=0\)
3.gia tri cua bieu thuc Q=(3+1)(32+1)(34+1)...(33994+1)
Cho bieu thuc \(A=\left(\frac{x+1}{x-1}-\frac{x-1}{x+1}+\frac{x^2-4x-1}{x^2-1}\right).\frac{x+2016}{x}\)
a, Voi gia tri nguyen nao cua x thi bieu thuc A co gia tri nguyen
b,Voi gia tri nao cua x thi A co gia tri duong
\(\frac{6}{x-3}+\frac{2x^2}{^{x^2}-1}+\frac{6-2x}{x^{3^{ }}-3x^2-x+3}\)
a / Rut gon A
b/ Tim x thuoc Z de A thuoc Z
c/ Tinh gia tri cua A khi x = căn 2
Tim cac gia tri nguyen cua x de phan thuc sau co gia tri nguyen:
\(A=\frac{2x^3-6x^2+x-8}{x-3}\)
\(B=\frac{x+2}{x+4}\)
cho 2 bieu thuc:
\(A=\frac{3}{2-x}-\frac{3}{x+2}+\frac{3x^2}{x^2-4}\) va \(B=\frac{x+1}{x+2}\)
a.Rut gon A
b.tim gia tri nguyen cua x de P=A:B co gia tri nguyen
