Explicație pas cu pas:
[tex]2d = a + b = a + 18 + a = 2a + 18 \\ d = a + 9 \\ a + 18 + a + 3a + a + 9 = 132 \\ 6a = 105 \\ a = \frac{35}{2} \\ b = 18 + \frac{35}{2} = > b = \frac{71}{2} \\ c = 3 \times \frac{35}{2} = > c = \frac{105}{2} \\ d = \frac{35}{2} + 9 = > d = \frac{53}{2} [/tex]
