If equations a x 2 + b x + c = 0 ,   a ,   b ,   c ∈ R ,   a ≠ 0 and 2 x 2 +…

If equations ax2+bx+c=0, a, b, cR, a0 and 2x2+3x+4=0  have a common root, then a:b:c equals :
  1. 2:3:4
  2. 4:3:2
  3. 1:2:3
  4. 3:2:1

Solution

ax2+bx+c=0          ....(i)

2x2+3x+4=0           ....(ii)

For equation (ii), D=9-424=-23<0

Roots are complex conjugates.

 Both roots are common in equation (i) and (ii).

∴    a 2 = b 3 = c 4

⇒ a : b : c : : 2 : 3 : 4

Asked in: JEE Main 2014 (09 Apr Online)

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