Răspuns:
[tex]\dfrac{7}{4}[/tex]
Explicație pas cu pas:
[tex]\displaystyle{ 1\frac{1}{4} - \frac{2}{7} + 3\frac{1}{2} - \frac{3}{14} = }[/tex]
[tex]\displaystyle{ = \frac{1 \cdot 4 + 1}{4} - \frac{2}{7} + \frac{3 \cdot 2 + 1}{2} - \frac{3}{14} }[/tex]
[tex]\displaystyle{ = \frac{5}{4} - \frac{2}{7} + \frac{7}{2} - \frac{3}{14} }[/tex]
Numitorul comun este 28 deci amplificam prima fractie cu 7, a doua cu 4, a treia cu 14 si ultima cu 2.
[tex]\displaystyle{ = \frac{5 \cdot 7 - 2 \cdot 4 + 7 \cdot 14 - 3 \cdot 2}{28} }[/tex]
[tex]\displaystyle{ = \frac{35-8+28-6}{28} }[/tex]
[tex]\displaystyle{ = \frac{27 + 28 - 6}{28} }[/tex]
[tex]\displaystyle{ = \frac{55-6}{28} }[/tex]
[tex]\displaystyle{ = \frac{49}{28}^{(7} }[/tex]
[tex]\displaystyle{ = \frac{7}{4} }[/tex]
