bayangan garis I yang melalui titik (2,1) gradien 3

y-y = m(x-x1)
y-1 = 3 (x-2)
y-1 = 3x - 6
maka bayangan garisnya adalah
= 3x-y-5=0

y-y1 = m(x-x1)
<=> y-1 = 3(x-2)
<=> y-1 = 3x-6
<=> y = 3x-6+1
<=> y = 3x-5 => eksplisit
<=> 3x-y-5 = 0 => implisit