B = 1 bạn nhé , đúng 100000000000% luôn

x= 0,4 bạn nhé

x = -0,4 bạn nhé

a)\(M_{max}=4\)

b) \(N_{max}=\frac{1}{3}\)

giải hẳn ra bạn ơi

Tính 2A rồi tính 2A - A là ra A

\(A=\frac{1}{2}+\left(\frac{1}{2}\right)^2+\left(\frac{1}{2}\right)^3+....+\left(\frac{1}{2}\right)^{99}\)

\(=\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+...+\frac{1}{2^{99}}\)

\(2A=1+\frac{1}{2}+\frac{1}{2^2}+....+\frac{1}{2^{98}}\)

\(2A-A=\left(1+\frac{1}{2}+\frac{1}{2^2}+....+\frac{1}{2^{98}}\right)-\left(\frac{1}{2}+\frac{1}{2^2}+\frac{1}{2^3}+....+\frac{1}{2^{99}}\right)\)

\(A=1-\frac{1}{2^{99}}=\frac{2^{99}-1}{2^{99}}\)

= 1/10

\(A=\frac{1+3^4+3^8+3^{12}}{1+3^2+3^4+3^6+3^8+3^{10}+3^{12}+3^{14}}\)

Ta có :

\(1+3^4+3^8+3^{12}=\left(3^{16}-1\right):\left(3^4-1\right)\)

\(1+3^2+3^4+3^6+3^8+3^{10}+3^{12}+3^{14}=\left(3^{16}-1\right):\left(3^2-1\right)\)

\(\Rightarrow A=\frac{\left(3^{16}-1\right):\left(3^4-1\right)}{\left(3^{16}-1\right):\left(3^2-1\right)}=\frac{3^2-1}{3^4-1}=\frac{1}{10}\)

\(\frac{3a+7b}{7a+3b}=1\)

=> 3a + 7b = 7a + 3b

=> 3a - 3b = 7a - 7b 

=> 3(a - b) = 7(a - b)

=> 7(a - b) - 3(a - b) = 0

=> 4(a - b) = 0

=> a - b = 0

=> a = b

Ta có : A = -a + b - 1

=> A = -a + a - 1

=> A = -1

cick mình nha bạn

3a+7b=7a+3b => a=b

-a+b-1=-a+a-1=-1