Let y=mx be a common line to both 2x2+ax(mx)+3m2x2=0 and 2x2+bx(mx)−3m2x2=0 Common from x2 in both equation, and 2+ma+3m2=0 2+mb−3m2=0 Adding both equation, we get m(a+b)=−4 ⇒m=
−4
a+b
Subtracting both equations, we get m(a−b)+6m2=0 ⇒m≠0, so m=
