9 класс геометрия помогите прошууу - вопрос №467607

1) AB = {4; 2}

AD = {2; -4}

3AD = {6; — 12}

CA = {-6; 2}

-0,5CA = {3; -1}

a = AB + 3AD + (-0,5CA)

a = {13; -11}

2) a = 13i — 11j

3) AB:

(X — Xa)/(Xb — Xa) = (Y — Ya)/(Yb — Ya)

(x — (-2)) / (2 — (-2)) = (y — 0) / (2 — 0)

(x + 2)/4 = y/2

2(x + 2) = 4y

x + 2 = 2y

x — 2y + 2 = 0

BC:

(X — Xb)/(Xc — Xb) = (Y — Yb)/(Yc — Yb)

(x — 2)/(4 — 2) = (y — 2)/(-2 — 2)

(x — 2)/2 = (y — 2)/(-4)

-4(x — 2) = 2(y — 2)

2(x — 2) = -(y — 2)

2x — 4 = -y + 2

2x + y — 6 = 0

AC:

(X — Xa)/(Xc — Xa) = (Y — Ya)/(Yc — Ya)

(x + 2)/(4 + 2) = (y — 0)/(-2 — 0)

(x + 2)/6 = y/(-2)

-2(x + 2) = 6y

x + 2 = -3y

x + 3y + 2 = 0

BD:

(X — Xb)/(Xd — Xb) = (Y — Yb)/(Yd — Yb)

(x — 2)/(0 — 2) = (y — 2)/(-4 — 2)

(x — 2)/(-2) = (y — 2)/(-6)

-6(x — 2) = -2(y — 2)

3(x — 2) = y — 2

3x — 6 = y — 2

3x — y — 4 = 0