Question

A= -1/21 + -1/28 

 

B= -8/18 - 15/27 

 

C= -5/12 + 0,75 

 

D= 3,5-{-2/7}

tính giá trị biểu thức nha giúp tui đi 

Answer 1

giúp tui đi

 

 

Answer 2

A = - \(\dfrac{1}{21}\) - \(\dfrac{1}{28}\)

A =- \(\dfrac{4}{84}\)- \(\dfrac{3}{84}\)

A = -\(\dfrac{7}{84}\)  

A = - \(\dfrac{1}{12}\)

B = - \(\dfrac{8}{18}\) - \(\dfrac{15}{27}\)

B = - \(\dfrac{4}{9}\) - \(\dfrac{5}{9}\)

B = -1

C = -  \(\dfrac{5}{12}\) + 0,75

C =  -\(\dfrac{5}{12}\) + \(\dfrac{3}{4}\)

C = - \(\dfrac{5}{12}\) + \(\dfrac{9}{12}\)

C = \(\dfrac{4}{12}\)

C= \(\dfrac{1}{3}\)

D = 3,5 - { - \(\dfrac{2}{7}\))

D = \(\dfrac{7}{2}\) + \(\dfrac{2}{7}\)

D = \(\dfrac{49}{14}\) + \(\dfrac{4}{14}\)

D = \(\dfrac{53}{14}\)