Question

The value of k, so that the equation -2x2 + xy + y2 -5x + y + k = 0 may represent a pair of S straight line is + 2 vy0 (A) -2 icio ) none of these (B) 2

JEE/Engineering Exams

Maths

Solution

174

4.0 (1 ratings)

( begin{aligned} H_{i} varphi & a=-2 b &=1 h &=frac{1}{2} end{aligned} mid begin{array}{l}c=k g=-5 / 2 f=frac{1}{2}end{array} ) [ 96 c+2 n f g-9 f^{2}-6 g^{2}-c h^{2}=0 ] ( -2 k+left(-frac{5}{4}right)-left(-frac{1}{2}right)-1left(frac{25}{4}right)-kleft(frac{1}{4}right)=0 ) ( -2 k-frac{5}{4}+frac{1}{2}-frac{25}{4}-frac{k}{4}=0 ) [ begin{array}{c} -8 k-5+2-25-k=0 -9 k=28 left.k=-frac{28}{9}right) end{array} ]