Question

Nhờ mọi người giúp mình vs!

Tìm x thuộc Q khi:

a)3^x-1 =243

b)\(\left(\dfrac{2}{3}\right)^{x+1}=\dfrac{8}{4}\)

c) 3^x+3^x+2=270

d) \(\left(x-\dfrac{5}{2}\right)^2=144\)

e) \(\left(2x+1\right)^3=\dfrac{215}{27}\)

f) (2x-1)⁵ = -243

h) (27-1)² = (2x-1)²

i) (2x+1)² + (x+1)¹⁰ = 0

k) \(\dfrac{x-2}{5}=\dfrac{X+3}{2}\)

l) \(\dfrac{2}{x}=\dfrac{x}{50}\)

m) \(\dfrac{\left(x-3\right)}{4}=\dfrac{4}{x+3}\)

n) \(|x+\dfrac{3}{5}|-|x-\dfrac{7}{3}|\)

Answer 1

a.\(3^{x-1}=243\)

\(3^x:3^1=243\)

\(3^x=729\)

\(\Leftrightarrow3^6=729\)

\(\Leftrightarrow x=6\)

b.\(\left(\dfrac{2}{3}\right)^{x+1}=\dfrac{8}{4}\)

\(\left(\dfrac{2}{3}\right)^x.\left(\dfrac{2}{3}\right)=\dfrac{8}{4}\)

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

Câu b tính đến đây rồi không mò đc x nữa.