f(x)x^2-4x-5 lalu carilah f^-1(x) = (inverse)

Fungsi Invers

f(x) = y = x² - 4x - 5
y = x² - 4x + 4 - 9
y = (x - 2)² - 9
(x - 2)² = y + 9
x - 2 = ± √(y + 9)
x = 2 ± √(y + 9)

Maka,
f^-1 (x) = 2 ± √(x + 9)

y=x²-4x-5
x²-4x-5-y=0
x²-4x-(5+y)=0
gunakan rumus abc

x=-(-4)±√(-4)²-(4).(1).-(5x+y)/2
x=4±√16+20+4y/2
x=4±√36+4y/2
x=4±√4(9+y)/2
x=4±2√9+y/2
x=2±√9+y

f^-1(x)=2±√9+x