a=ti-2j+hk dan b=(t+2)i+2j+3k jika a=-b maka vektor a adalah

a = (t, -2, h)
b = (t+2, 2, 3)
a = -b
(t, -2, h) = -(t+2, 2, 3)
(t, -2, h) = (-t-2, -2, -3)
Jelas h = -3
t = -t - 2
<=> 2t = -2
<=> t = -1

Maka vektor a = (-1, -2, -3) = -1i - 2j - 3k.