tentukan invers fungsi y=2x²+3x-1

f(x) = 2x^2 + 3x - 1

f(x) = y
2x^2 + 3x - 1 = y
x^2 + 3x/2 - 1/2 = y/2
x^2 + 3x/2 = y/2 + 1/2
x^2 + 3x/2 + 9/16 = y/2 + 1/2 + 9/16
(x + 3/4)^2 = y/2 + 8/16 + 9/16
(x + 3/4)^2 = y/2 + 17/16
x + 3/4 = akar(y/2 + 17/16)
x = -3/4 + akar(y/2 + 17/16)
f(x)^-1 = -3/4 + akar(x/2 + 17/16)
f(x)^-1 = -3/4 + akar((8x + 17)/16)