Câu hỏi của Lê Huyền Trang

Question

Tìm GTLN (hoặc GTNN) của:

a) A=3x^2+8x+54

b) B=-x^2+4x-9

Nguyễn Việt Lâm · Accepted Answer

$A=3\left(x+\frac{4}{3}\right)^2+\frac{146}{3}\ge\frac{146}{3}$

$A_{min}=\frac{146}{3}$ khi $x=-\frac{4}{3}$

$B=-\left(x-2\right)^2-5\le-5$

$B_{max}=-5$ khi $x=2$Câu trả lời: $A=3\left(x+\frac{4}{3}\right)^2+\frac{146}{3}\ge\frac{146}{3}$

$A_{min}=\frac{146}{3}$ khi $x=-\frac{4}{3}$

$B=-\left(x-2\right)^2-5\le-5$

$B_{max}=-5$ khi $x=2$