6.
Hasło: Francois Viete
7.
[tex]x = 3\\\\\underline{3x-5 = 4}\\\\\\y = -5\\\\\underline{\frac{y-3}{2} = -4}\\\\\\z = \frac{2}{3}\\\\\underline{7-3z = 5}\\\\\\t = 0,5\\\\\underline{\frac{2-t}{3} = 0,5}[/tex]
8.
[tex]a = 7\\\\\underline{4a+22 = 50}\\\\\\b = 3\\\\\underline{2\cdot b + 2 = 8}\\\\\\c = 3\\\\\underline{\frac{c}{2+4} = \frac{1}{2}}\\\\\\d = -5\\\\\underline{10-d = 15}[/tex]
9.
[tex]a)\\5x-7+2x+8-6x = 10\\\\x + 1 = 10\\\\\boxed{x = 9}\\\\\\b)\\4y-5+4y-2y+5-3y = 9\\\\3y = 9\\\\\boxed{y = 3}[/tex]
