Question

tim gia tri lon nhat cua phan thuc 

A=3x+1

2x²-x+3

Answer 1

= 1/4 nhe

Answer 2

Câu 2:

  \(=2\left(x^2-\frac{1}{2}+\frac{3}{2}\right)\)

  \(=2\left(x^2-\frac{1}{2}+\left(\frac{1}{4}\right)^2-\left(\frac{1}{4}\right)^2+\frac{3}{2}\right)\)

   \(=2\left(\left(x-\frac{1}{4}\right)^2+\frac{23}{16}\right)\)

   \(=2\left(x-\frac{1}{4}\right)^2+2.\frac{23}{16}\)

   \(=2\left(x-\frac{1}{4}\right)^2+\frac{23}{8}\le\frac{23}{8}\)

Vậy MaxB = \(\frac{23}{8}\Leftrightarrow x-\frac{1}{4}=0\)

                            \(\Leftrightarrow x=\frac{1}{4}\)

   

Answer 3

x = 1/4 nhé