Răspuns :
Răspuns:
Ecuatia dreptei
(y-yA)/(yB-yA)=(x-xA)/(xB-xA)
(y-(-1))/(-2-(-1))=(x-2)(1-2)
(y+1)/(-1)=(x-2)/(-1)
y+1=x-2
y=x-2-1
y=x-3
Explicație pas cu pas:
[tex]\it AB:\ \ \dfrac{x-x_A}{x_B-x_A}=\dfrac{y-y_A}{y_B-y_A} \Rightarrow \dfrac{x-2}{1-2}=\dfrac{y+1}{-2+1} \Rightarrow 2-x=-y-1 \Rightarrow \\ \\ \\ \Rightarrow x-y-3=0[/tex]