b) f(1) + 2f(-2) = a - 1 + 2(a - 1).(-2) = a - 1 - 4a + 4 = -3a + 3 = -3(a - 1) = f(-3) (đpcm)

còn câu a nữa mà bạn:<

mk

Tôi tuần sau ms thi

a=8 => b=9 hoặc b=10

a=9 => b=10

Vì:\(7< a< 11\)

Nên:\(a=8\) hoặc  \(a=9\)

\(\Rightarrow b=10\)

Vậy:\(a=8\) hoặc \(a=9;b=10\)

*Tham khảo:

Hey [Friend's Name],

I just wanted to tell you about the smartphone I recently chose. After doing a lot of research, I ended up selecting the new [Smartphone Model]. It has an amazing camera, long battery life, and a super-fast processor. The display is also stunning, and it has all the features I was looking for. I'm really excited about it and can't wait to show it to you. Let's plan to catch up soon so I can give you a demo!

Take care,
[Your Name]

trong hóa học k có chất My

\(\left|x-3,2\right|+\left|2x-\frac{1}{5}\right|=x+3.\)

ĐK : \(x+3\ge0\Leftrightarrow x\ge-3\)

Th1 : \(x-3,2+2x-\frac{1}{5}=x+3\)

\(x-3,2+2x=x+\frac{16}{5}\)

\(x+2x=x+\frac{32}{5}\)

\(2x=\frac{32}{5}\)

\(\Leftrightarrow x=3,2\)(tm)

\(x-3,2+2x-\frac{1}{5}=3-x\)

\(x-3,2+2x=3-x+\frac{1}{5}\)

\(x-3,2+2x=\frac{16}{5}-x\)

\(x+2x=\frac{16}{5}-x+3,2\)

\(x+2x=\frac{32}{5}-x\)

\(2x=\frac{32}{5}-x-x\)

\(2x=\frac{32}{5}-2x\)

\(4x=\frac{32}{5}\)

\(x=1,6\)(tm)

Vậy \(x=1,6\)hoặc \(x=3,2\)

#)Thắc mắc ? 

Cho mk hỏi cái ''với 2'' là j bn ? so sánh ak, nếu là so sánh thì mk giải thế này :

#)Giải :

\(M=\frac{2}{1.2}+\frac{2}{2.3}+\frac{2}{3.4}+...+\frac{2}{49.50}\)

\(M=2-1+1-\frac{2}{3}+\frac{2}{3}-\frac{2}{4}+...+\frac{2}{48}-\frac{2}{49}+\frac{2}{49}-\frac{2}{50}\)

\(M=2-\frac{2}{50}\)

\(M=1\frac{24}{25}=\frac{49}{25}\)

So sánh \(\frac{49}{25}\)với  2

\(2=\frac{2}{1}=\frac{50}{25}\)

Vì \(\frac{49}{25}< \frac{50}{25}\Rightarrow\frac{49}{25}< 2\Rightarrow M< 2\)

          #~Will~be~Pens~#

\(M=\frac{2}{1.2}+\frac{2}{2.3}+...+\frac{2}{49.50}=2\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{49}-\frac{1}{50}\right)=2\left(1-\frac{1}{50}\right)=2x\frac{49}{50}=\frac{49}{25}=1\frac{24}{25}\)

Vì M=1 24/25

=>M<2