Cho x+y-2=0.tinh gia tri cua da thuc :M=x^3+×^2y-xy-y^2×3y+x-1
tinh gia tri cua cac da thuc sau biet x+y-2=0.M=x^4+2x^3y-2x^3+x^2y^2-2x^2y-x(x+y)+2x+3
Cho x-y=2,tim gia tri nho nhat cua da thuc Q=xy+4
Cho ti le thuc 2x-y/x+y=3/4. Tim gia tri cua tiso x/y.
Tim gia tri nho nhat cua bieu thuc sau:
A = x^2+xy+y^2-3x+3y
Bai 5
a)Tim gia tri lon nhat cua A=2016 phan (x-2)2 +(x-y)4+3
b)Tim cac gia tri cua x sao cho A=7-x phan x+2 co gia tri duong
biet x+y=3 tim gia tri cua x va y de tich xy lon nhat
bai 1: Cho cac don thuc A=-4/9x^3y va B= 3/8 x^5y^3. Tim cac cap gia tri (x;y)de A,B cung gia tri am
bai 2: viet don thuc B=64xy^12 duoi dang luy thua cua 1 don thuc voi so mu khac 1
bai 3: cho A=8x^5y^3; B=-3x^6y^3; C=-6x^7y^2. CM: Ax^2+Bx+C>0
tim gia tri max cua xy biet x+y=1