Răspuns:
Explicație pas cu pas:
a). [tex](\frac{1}{2} +\frac{1}{5} )*\frac{30}{49} +\frac{5}{7} =(\frac{5}{10} +\frac{2}{10} )*\frac{30}{49} +\frac{5}{7} =\frac{7}{10} *\frac{30}{49} +\frac{5}{7} =\frac{3}{7} +\frac{5}{7} =\frac{8}{7}[/tex]
b). 2 1/2*4/25+7/25+7/15*3/14=5/2*4/25+7/15*3/14=2/5+1/10=4/10+1/10=5/10=1/2
c). (3 1/2-1 2/3)*36/55=(7/2-5/3)*36/55=(21/6-10/6)*36/55=11/6*36/55=6/5
d). 2/3*(1 1/5+2 1/2)-(1/2+1/4+1/3)=2/3*(6/5+5/2)-(6/12+3/12+4/12)=
=2/3*(12/10+25/10)-13/12=2/3*37/10-13/12=1/3*37/5-13/12=37/15-13/12=
=148/60-65/60=83/60
