\(\overrightarrow{AB}=\left(x_B-x_A;y_B-y_A\right)=\left(3;-9\right)\)

Gọi \(M\left(0;m\right)\Rightarrow\left\{{}\begin{matrix}\overrightarrow{AM}=\left(-1;m+2\right)\\\overrightarrow{AB}=\left(-5;7\right)\end{matrix}\right.\)

3 điểm M;A;B thẳng hàng khi:

\(\dfrac{-1}{-5}=\dfrac{m+2}{7}\Rightarrow m=-\dfrac{3}{5}\)

\(\Rightarrow M\left(0;-\dfrac{3}{5}\right)\)

x I = 2 + 4 2 = 3 y I = − 3 + 7 2 = 2 ⇒ I 3 ; 2 .

Đáp án C

x I = 2 + 4 2 = 3 y I = − 3 + 7 2 = 2 ⇒ I 3 ; 2 .

Đáp án C