Ta có :
A = 2x2 - 10x + 11
= 2( x2 - 2.x.\(\frac{5}{2}\) + \(\frac{25}{4}\) ) - \(\frac{3}{2}\)
= 2(x - \(\frac{5}{2}\))2 - \(\frac{3}{2}\)
Ta có :
(x - \(\frac{5}{2}\))2 \(\ge0\)
<=> 2(x - \(\frac{5}{2}\))2 \(\ge0\)
<=> 2(x - \(\frac{5}{2}\))2 - \(\frac{3}{2}\) \(\ge-\frac{3}{2}\)
Vậy Amin = - \(\frac{3}{2}\) [ Khi (x - \(\frac{5}{2}=0=>x=\frac{5}{2}\))
Cho bieu thuc \(Q=\frac{x}{x^2-3x+9}-\frac{11}{x^3+27}+\frac{1}{x+3}:\frac{x^2-1}{x+3}\)
a)Tim DKXD cua bt Q
b)Rut gon
c)Tim GTLN
d)Co gtri nguyen nao cua x de Q có gtri nguyên hay k
gia tri nho nhat cua bieu thuc
M=/x+3/+/x-5/
tinh gt cua bieu thuc
(x+2).(2x+2x^2)/(x+1).(4x-x^2)
với x=-1/2
Tinh gia tri bieu thuc
1/(2016^-2016+1)+1/(2016^-2015+1)+.....+1/(2016^-1+1)+1/(2016^0+1)+1/(2016^1+1)+....+1/(2016^2016+1)
2. Tim bo 3 so nguyen duong a,b,c biet
ac=b(a-b+c) và 1/a+1/b+1/c=1
3. Tim cac cap so thuc x,y co tich la 1 sao cho
(x+y-2)/4=1/(x-1)+1/(y-1)
Chung minh rang bieu thuc sau luon co gia tri duong voi moi gia tri cua x
B=x4-2x3+2x2-4x+5
tim gtnn cua B=x^3+y^3+xy biet x+y=1
Cho a+b+c=0. Rut gon bieu thuc M=a3+b3+c(a2+b2)-abc
cho da thuc : g(x) = x^3+2x^2-2x-12
Phan tich g(x) thanh tich cua nhi thuc x-2 voi mot tam giac bac 2
BT1: Tìm GTNN a) A=x^2-4xy+5y^2+10x-22y+2017 b) B=x^2+y^2-xy-x+y+1 GIÚP MÌNH VỚI NHA THỨ 6 MÌNH PHẢI NỘP RỒI
