Question

Find the equation of the line which passes through the point (– 4, 3) and the portion of the line intercepted between the axes is divided internally in the ratio 5 : 3 by this point.

Answer 1

Let AB be a line passing through a point (– 4, 3) and meets x-axis at A(a, 0) and y-axis at B(0, b).

∴ – 4 = `(5 xx 0 + 3a)/(5 + 3)`

⇒ – 4 = `(3a)/8`  .....`[(because  "X" = (m_1x_2 + m_2x_1)/(m_1 + m_2)),("and"  "Y" = (m_1y_2 + m_2y_1)/(m_1 + m_2))]`

⇒ 3a = – 32

∴ a = `(-32)/3`

And 3 = `(5.b + 3.0)/(5 + 3)`

⇒ 3 = `(5.b)/8`

⇒ 5b = 24

⇒ b = `24/5`

Intercept form of the line is

`x/((-32)/3) + y/(24/5)` = 1

⇒ `(-3x)/32 + (5y)/24` = 1

⇒ – 9x + 20y = 96

⇒ 9x – 20y + 96 = 0

Hence, the required equation is 9x – 20y + 96 = 0.