a)
[tex]f(x) = \frac{2x-7}{(x-7)(x+1}[/tex]
x ≠ 7 i x ≠ -1
D = R \ {-1, 7}
b)
[tex]g(x) = \frac{4x}{\sqrt{7-2x}}[/tex]
7 - 2x > 0
-2x > -7 /:(-2)
x < 3,5
x ∈ (-∞; 3,5)
c)
[tex]h(x) = \frac{\sqrt{x-2}}{x^{2}-49}[/tex]
x - 2 ≥ 0 i x² - 49 ≠ 0
x ≥ 2 i (x + 7)(x - 7) ≠ 0
i x ≠ -7 i x ≠ 7
x ∈ < 2; 7)
