Explicație pas cu pas:
35)
[tex]x + \frac{x + 1}{2} + \frac{x + 2}{3} + ... + \frac{x + 9}{10} = 10 \\ [/tex]
[tex]2520x + 1260(x + 1) + 840(x + 2) + 630(x + 3) + 504(x + 4) + 420(x + 5) + 360(x + 6) + 280(x + 8) + 252(x + 9) = 25200 \\ [/tex]
[tex]7381x = 7381 \implies \bf x = 1[/tex]
40)
5x + 6y + 1 = 0
x = 1, y = -1
=>
5•1 + 6•(-1) + 1 = 5 - 6 + 1 = 6 - 6 = 0
