Answer:
y² - 2y - 4x + 9 = 0 (*)
a = 1 b = -2 c = -4x + 9
Δ = b² - 4ac = 4 - 4(9 - 4x) = 4 - 36 + 16x = 16x - 32
if (*) have the solutions => Δ ≥ 0
⇔ 16x - 32 ≥ 0 ⇔ x ≥ 2
with x ≥ 2 => y = [tex]\frac{2+\sqrt{16x-32} }{2}=\frac{2+4\sqrt{x-2} }{2}=1+2\sqrt{x-2}[/tex]
or y = [tex]1-2\sqrt{x-2}[/tex]
Step-by-step explanation:
