Ex 9.2, 12 - Chapter 9 Class 11 Straight Lines

Transcript

Ex 9.2, 13 Find equation of the line passing through the point (2, 2) and cutting off intercepts on the axes whose sum is 9. Equation of the line in intercept form is / + / = 1 where a = x - intercept & b = y-intercept Given that sum of intercepts is 9 a + b = 9 b = 9 a Putting value b = 9 a in equation / + /(9 ) = 1 Since point A(2, 2) lies on the line, it will satisfy the equation of line Putting x = 2 & y = 2 in the equation 2/ + 2/(9 ) = 1 ((9 a)2 + 2a)/(a(9 a)) = 1 18 2a + 2a = a(9 a) 18 0 = 9a a2 18 = 9a a2 a2 9a + 18 = 0 a2 6a 3a + 18 = 0 a(a 6) 3(a 6)= 0 (a 3) (a 6) = 0 So, a = 3 & a = 6