f(x) = 0,5×2 - 2х - 6.

Interpret 0,5 as 0.5. Then f(x) = 0.5 × 2 − 2x − 6 = 1 − 2x − 6 = −2x − 5.

Key facts:

• Domain: all real numbers
• f(x) = −2x − 5 (slope −2, y-intercept −5)
• x-intercept: set f(x) = 0 → −2x − 5 = 0 → x = −5/2 = −2.5
• The function is strictly decreasing.

If you meant a different parsing (e.g., 0,5×2x − 6), tell me and I’ll adjust.