Question

Tìm x biết;

a) 2^x+3 + 5. 2^x+2 = 224

b)4^x+1 - 4x = 48

c) 2^2x+2 + 3. 4^x+1 = 64

d) (x - 2/9)³ = (2/3)⁶

^{Các bạn giúp mk giải nhé! Mình đang cần.}

Answer 1

a) \(2^{x+3}+5.2^{x+2}=224\)

\(2.2^{x+2}+5.2^{x+2}=224\)

\(7.2^{x+2}=224\)

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

\(x+2=5\Leftrightarrow x=3\)

b) \(4^{x+1}-4^x=48\)

\(4.4^x-4^x=48\)

\(3.4^x=48\)

\(4^x=16=4^2\)

vậy x=2

c) \(2^{2\left(x+1\right)}+3.4^{x+1}=64\)

\(4^{x+1}+3.4^{x+1}=64\)

\(4.4^{x+1}=64\)

\(4^{x+2}=64=4^3\)

x+2=3

x=1

d) \(\left(x-\dfrac{2}{9}\right)^3=\left(\dfrac{2}{3}\right)^6\)

\(\left(x-\dfrac{2}{9}\right)^3=\left(\left(\dfrac{2}{3}\right)^2\right)^3\)

\(\left(x-\dfrac{2}{9}\right)^3=\left(\dfrac{4}{9}\right)^3\)

\(x-\dfrac{2}{9}=\dfrac{4}{9}\)

\(x=\dfrac{2}{3}\)