Odpowiedź:
prosta ab: y = a1 × x + b1
prosta równoległa do prostej ab: y = a2 × x + b2
ab = a2 = a
y = ax + b1
1 = a×(-2) + b1
3 = a×4 + b1
1 + 2a = b1
3 = 4a + 1 + 2a
2 = 6a
a = 1/3
y = ax + b2
y = 1/3x + b2
-7 = 1/3 × (-5) + b1
-7 = - 5/3 + b1
b1 = -7 + 5/3
b1 = -7 + 1 2/3
b1 = -5 1/3
y = 1/3x - 5 1/3
