Q6 of 112 Page 163

Find the equation of the straight line whose

(i) slope is –4 and passing through (1, 2) (ii) slope is and passing through (5, –4)

The equation of the line with the given slope m and passing through the point (x1, y1) is given by the slope–point form


y– y1 = m (x – x1)


(i) Here given the slope (m) = –4 and the point = (1,2)


Thus the equation of the line is


y–2 = –4(x – 1)


⇒ y –2 = –4x + 4


⇒ y = –4x + 6


⇒ 4x + y – 6 = 0


(ii) Here given slope (m) = 2/3 and point = (5,–4)


Thus the required equation is



⇒ 3y + 12 = 2x –10


⇒ –2x + 3y + 22 = 0


⇒ 2x – 3y – 22 = 0


More from this chapter

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4

Find the equation of the line intersecting the y- axis at a distance of 3 units above the origin and tan , where θ is the angle of inclination.

 5

Find the slope and y–intercept of the line whose equation is

(i) y = x + 1 (ii) 5x = 3y (iii) 4x – 2y + 1 = 0 (iv) 10x + 15y + 6 = 0

 7

Find the equation of the straight line which passes through the midpoint of the line segment joining (4, 2) and (3, 1) whose angle of inclination is 30°.

 8

Find the equation of the straight line passing through the points

(i) (–2, 5) and (3, 6) (ii) (0, –6) and (–8, 2)