aidé moi svp on donne a=5/3 et b=10/21 calculer. a) a+b         b) a-b            c)ab

on donne a=5/3 et b=10/21 calculer.
a) a+b =5/3+10/21
          =35/21+10/21
          =45/21
          =15/7     

b) a-b =5/3-10/21
         =35/21-10/21
         =25/21

c) ab =5/3*10/21
        =50/63

[tex]a + b = \frac{5}{3} + \frac{10}{21} = \frac{7*5}{7*3} + \frac{10}{21} = \frac{35}{21} + \frac{10}{21} = \frac{45}{21} = \frac{3*15}{3*7} = \frac{15}{7} [/tex]

[tex]a - b = \frac{5}{3} - \frac{10}{21} = \frac{35}{21} - \frac{10}{21} = \frac{25}{21} [/tex]

[tex]a*b = \frac{5}{3}* \frac{10}{21} = \frac{5*10}{3*21} = \frac{50}{63} [/tex]