Question

Tính a) 1/7 × (4/3)^2 - 1/7 : 9/11 b) tìm x biết 2x + 1/4 = 3/5

Answer 1

a, \(\dfrac{1}{7}\) x ( \(\dfrac{4}{3}\))² - \(\dfrac{1}{7}\) : \(\dfrac{9}{11}\) 

= \(\dfrac{1}{7}\) x  \(\dfrac{16}{9}\)   -   \(\dfrac{1}{7}\) x \(\dfrac{11}{9}\)

= \(\dfrac{1}{7}\) x ( \(\dfrac{16}{9}-\dfrac{11}{9}\))

= \(\dfrac{1}{7}\) x \(\dfrac{5}{9}\)

= \(\dfrac{5}{63}\)

b, 2x + \(\dfrac{1}{4}\) = \(\dfrac{3}{5}\)

    2x         = \(\dfrac{3}{5}-\dfrac{1}{4}\)

   2x          = \(\dfrac{7}{20}\)

     x          =  \(\dfrac{7}{20}:2\)

     x          = \(\dfrac{7}{40}\)