In a ABC, suppose y=x is the equation of the bisector of the angle B and the equation of the side AC is 2x-y=2. If 2AB=BC and the points A and B are respectively (4,6) and ( , ), then +2 is equal to
- 42
- 39
- 48
- 45
Answer
(1) 42
Solution
B on y=x =
Bisector meets AC at D: y=x, 2x-y=2 D(2,2)
∵ AD:DC=AB:BC=1:2 D= 2A+C3 C=3D-2A=(-2,-6)
∵ y=x bisects B, the image A (6,4) of A lies on BC
[figure]
BC through C(-2,-6), A (6,4): y+6= 54(x+2)
With y=x: 4x+24=5x+10 x=14 B(14,14)
+2 =14+28=42
Answer: (1)