Răspuns:
[tex]a + b + c = s \\ \frac{5s}{17} + \frac{8s}{17} + 80 = s \\ \frac{13s}{17} - s = - 80 \\ \frac{13s}{17} - \frac{17s}{17} = - 80 \\ \frac{ - 4s}{17} = \frac{ - 80 \times 17}{17 } \\ - 4s = - 1360 \\ s = 1360 \div 4 \\ s = 340 \\ a = \frac{5 \times 340}{17} = 100 \\ b = \frac{8 \times 340}{17} = 160 \\ a + b = 100 + 160 = 260[/tex]
