1.
`\vec(AB) (-6;4) => \vecn(2;3)`
`=> PT : 2(x-1) + 3(y-1)=0`
`<=> 2x+3y -5=0`
2.
`\vecn(-3;4) => \vecu(4;3)`
`=>` PT : $\begin{cases}x=-5+4t\\y=2+3t\\\end{cases}$
3.
a)
`d` có `\vecu(1;-2) `
Mà `d ⊥ d'`
`=> \vecn_d'(1;-2)`
`=> \vecu_d'(2;1)`
`=>` PT : $\begin{cases}x=5+2t\\y=2+t\\\end{cases}$
`=> (x-5)/2 = (y-2)/1`
b)
`d` // `d'`
`=> \vecu_d'(-1;2)`
`=>` PT: $\begin{cases}x=5-t\\y=2+2t\\\end{cases}$
`=> (x-5)/(-1) = (y-2)/2`