Question

A straight line L1 has a gradient ˉ½ and passes through point P (−1, 3). Another line L2 passes through the points Q (1, -3) and R (4, 5). Find.

1. The equation of L1. 
2. The gradient of L2.
3. The equation of L2. 
4. The equation of a line passing through a point S (0, 5) and is perpendicular to L2. 
5. The equation of a line through R parallel to L1.

Answer 1

1. y−3 =½
   x+1
   y−3 =−½x −½
   y=−½x + ⁵/₂
2. g= 5−−3
        4−1
      =⁸/₃
3. y−5 = 8
   x−4    3
   y−5 = ⁸/₃x − ³²/₃ 
   y = ⁸/₃x − ³²/₃ +5
   y = ⁸/₃x − ¹⁷/₃
4. y−5 × − 3
    x          8
   y = ⁻³/₈x + 5
5. y−5= −½
   x−4
   y−5 =−½x +2
   y=−½x + 7