Răspuns:
a) aducem la acelasi numitor 8 , adica inmultim a doua fractie cu 2
[tex]\frac{5+2*1}{8}[/tex] * 12= [tex]\frac{7}{8}[/tex] *12= [tex]\frac{7*12}{8} = \frac{7*3}{2} = \frac{21}{2}[/tex]
b) [tex]\frac{4-3}{15}[/tex] * 25= [tex]\frac{1* 25}{3*5} = \frac{5*5}{3*5} =\frac{5}{3}[/tex]
c) [tex]\frac{3*3-7}{12}[/tex] * 9= [tex]\frac{2*9}{2*6}[/tex]= [tex]\frac{3*3}{2*3} = \frac{3}{2}[/tex]
d) [tex]\frac{7+3}{15}[/tex] * 3= [tex]\frac{10* 3}{3*5} =\frac{5*2}{5} = 2[/tex]
e) [tex]\frac{9-1}{21}[/tex] * 14= [tex]\frac{8 * 14}{21} = \frac{8*7*2}{3*7} = \frac{16}{3}[/tex]
f)[tex]\frac{9-1}{9}[/tex] *3= [tex]\frac{8*3}{9} =\frac{8*3}{3*3} =\frac{8}{3}[/tex]
