help me plesa
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
![](https://rs.olm.vn/images/avt/0.png?1311)
![](https://rs.olm.vn/images/avt/0.png?1311)
F = x4 - 2x2 + 3 = x4 - 2x2 + 1 + 2 = (x2 - 1)2 + 2 \(\ge2\)
=> Min F = 2
Dấu "=" xảy ra <=> x2 - 1 = 0
<=> x = \(\pm1\)
Vậy Min F = 2 <=> x = \(\pm1\)
Ta có G = (x2 + 2)2 - 3
= x4 + 4x2 + 1 = x2(x2 + 4) + 1 \(\ge1\)
=> Min G = 1
Dấu "=" xảy ra <=> x2(x2 + 4) = 0
<=> x = 0
Vậy Min G = 1 <=> x = 0
![](https://rs.olm.vn/images/avt/0.png?1311)
a, 1,5 +|2x - 2/3| = 3/2
|2x - 2/3| = 3/2 - 1,5
|2x - 2/3| = 0
<=> 2x - 2/3 = 0
<=> 2x = 0 + 2/3
<=> 2x = 2/3
<=> x = 2/3 : 2
<=> x = 1/3
Vậy x = 1/3
b, 3/4 - |1/4 - x| = 5/8
|1/4 - x| = 3/4 - 5/8
|1/4 - x| = 1/8
<=> 1/4 - x = 1/8
1/4 - x = /1/8
<=> x = 1/4 - 1/8
x = 1/4 - ( -1/8)
<=> x = 1/8
x = 3/8
Vậy x thuộc { 1/8 ; 3/8 }
![](https://rs.olm.vn/images/avt/0.png?1311)
=1/1-7-1/-5+1/2
=1/-2+1/2
=1
k nha đúng
\(\frac{1}{1-3}-\frac{1}{3-5}+\frac{1}{7-5}\)
\(=\frac{1}{-2}-\frac{1}{-2}+\frac{1}{2}\)
\(=\frac{-1}{2}+\frac{1}{2}+\frac{1}{2}\)
\(=0+\frac{1}{2}=\frac{1}{2}\)
\(C=-\left(\frac{3}{7}+\frac{3}{8}\right)-\left(-\frac{3}{8}+\frac{4}{7}\right).\)
\(C=-\frac{45}{56}-\frac{11}{56}\)
\(C=-1\)
\(C=-\left(\frac{3}{7}+\frac{3}{8}\right)-\left(-\frac{3}{8}+\frac{4}{7}\right)\)
\(C=-\frac{3}{7}-\frac{3}{8}+\frac{3}{8}-\frac{4}{7}\)
\(C=-\frac{3}{7}-\frac{4}{7}\)
\(C=-\frac{7}{7}=-1\)