Quay lại đáp án

A=2x^2+9y^2-6xy-6x-12y+2024 A = (x^2 -6xy +9y^2) + 4(x -3y) + x^2 - 10x + 2024A = (x -3y)^2 +4(x -3y) + 4 + x^2 -10x +25 + 1995A = (x -3y +2)^2 + (x -5)^2 + 1995 1995Min A = 1995 x - 5 = 0 => x = 5Và x - 3y + 2 = 0 hay 5 -3y +2 = 0 => -3y = -7 => y = 7/3

A=2x^2+9y^2-6xy-6x-12y+2024 A = (x^2 -6xy +9y^2) + 4(x -3y) + x^2 - 10x + 2024A = (x -3y)^2 +4(x -3y) + 4 + x^2 -10x +25 + 1995A = (x -3y +2)^2 + (x -5)^2 + 1995 1995Min A = 1995 x - 5 = 0 => x = 5Và x - 3y + 2 = 0 hay 5 -3y +2 = 0 => -3y = -7 => y = 7/3 B =-x^2+2xy-4y^2+2x+10y-8B = -x^2 + 2x(y -1) - 4y^2 + 10y - 8B = -x^2 + 2x(y-1) - (y-1)^2 + (y-1)^2 -4y^2 +10y -8B = -(x - y +1)^2 + y^2 - 2y +1 - 4y^2 + 10y - 8B = -(x - y+1)^2 + -3y^2 + 8y -7B = -(x -y+1)^2 - 3(y^2 + 8/3 y + 16/9 ) + 16/3 - 7B = -(x-y +1)^2 -3(y +4/3)^2 - 5/3 -5/3Max B = -5/3__ y + 4/3 = 0 => y =-4/3 Và ___ x - y + 1 = 0 Hay x -(-4/3) + 1 = 0=> x + 4/3 + 1 = 0 => x = -2/1/3