Question

Tìm GTNN:

B= 2x^2-14y+y^2-4x+16

Answer 1

\(B=2\left(x^2-2x+1\right)+\left(y^2-14y+49\right)-35\\ =2\left(x-1\right)^2+\left(y-7\right)^2-35\ge-35\)

dấu = xảy ra khi x=1,y=7

tick mik nha

Answer 2

Ta có: \(B=2x^2-4x+y^2-14y+16\)

\(=2\left(x^2-2x+1\right)+y^2-14y+49-34\)

\(=2\left(x-1\right)^2+\left(y-7\right)^2-34\ge-34\forall x,y\)

Dấu '=' xảy ra khi x=1 và y=7