The point A has coordinates (−2, 6). The equation of the perpendicular bisector of the line AB is 2y = 3x + 5.
- (i)Find the equation of AВ.[3]
- (ii)Find the coordinates of B.[3]
Mark scheme
Marking points from the official mark scheme (May/June 2017). The mark or mark type is shown in brackets.
- Gradient = 1.5 Gradient of perpendicular = -2/3
- [B1]
- Equation of AB is y-6 = -2/3(x+2) Or 3y+2x=14 oe
- [M1 A1] Correct use of straight line equation with a changed gradient and (–2, 6), the (-(-2)) must be resolved for the A1 ISW. Using y = mx + c gets A1 as soon as c is evaluated.
- Simultaneous equations → Midpoint (1, 4)
- [M1] Attempt at solution of simultaneous equations as far as x =, or y =.
- Use of midpoint or vectors → В (4, 2)
- [M1A1] Any valid method leading to x, or to y.
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