Question

2. tìm x

a. \(\dfrac{2}{3}x+1=\dfrac{7}{15}\)

b. \(3^{x+2}-3^x=24\)

c. \(\dfrac{x}{12}=\dfrac{5}{9}\)

d. \(\dfrac{-2}{3}:x+\dfrac{5}{8}=\dfrac{-7}{12}\)

Answer 1

a.\(\dfrac{2}{3}\)x +1=\(\dfrac{7}{15}\)

\(\dfrac{2}{3}x\) =\(\dfrac{7}{15}-\dfrac{15}{15}\)

\(\dfrac{2}{3}x\) =\(\dfrac{-8}{15}\)

\(x\) =\(\dfrac{-8}{15}:\dfrac{2}{3}\)

\(x\) = \(\dfrac{-4}{5}\)

Answer 2

c.\(\dfrac{x}{12}=\dfrac{5}{9}\)

➝\(x.9=12.5\)

➝\(x.9=60\)

➝\(x=\dfrac{60}{9}=\dfrac{20}{3}\)

Answer 3

d. đề

\(\dfrac{-2}{3}:x=\dfrac{-7}{12}-\dfrac{5}{8}\)

\(\dfrac{-2}{3}:x=\dfrac{-29}{24}\)

\(x=\dfrac{-2}{3}:\dfrac{-29}{24}\)

\(x=\dfrac{-2}{3}.\dfrac{-29}{24}\)

\(x=\dfrac{29}{36}\)