Răspuns:
Explicație pas cu pas:
a)
a*b=5/12
a*c = 9/20
a*d= 7/15
a*(b+c+d)
a*(b+c-d)
-
a*(b+c+d) = a*b+a*c+a*d= ⁵⁾5/12+³⁾9/20+⁴⁾7/15= 25/60+27/60+28/60=
80⁽¹⁰/60⁽¹⁰=8⁽²/6⁽²=4/3
-
a*(b+c-d) = a*b+a*c- a*d= ⁵⁾5/12+³⁾9/20-⁴⁾7/15=25/60+27/60-28/60=24⁽¹²/60⁽¹²=2/5