• Numerical Ability - Quadratic Equations
Question

I. 16x² + 20x + 6 = 0

II. 10y² + 38y + 24 = 0

  • A) if x < y
  • B) if x ≤ y
  • C) relationship between x and y cannot be determined
  • D) if x ≥ y
  • E) if x > y
Solution

Sol.

I. 16x² + 20x + 6 = 0 ⇒ 8x² + 10x + 3 = 0 ⇒ 8x² + 4x + 6x + 3 = 0 ⇒ (2x + 1) (4x + 3) = 0 ⇒ x = –1/2, –3/4

II. 10y² + 38y + 24 = 0 ⇒ 5y² + 19y + 12 = 0 ⇒ 5y² + 15y + 4y + 12 = 0 ⇒ (y + 3) (5y + 4) = 0 y = –3, –4/5 x > y

Sol.

I. 16x² + 20x + 6 = 0 ⇒ 8x² + 10x + 3 = 0 ⇒ 8x² + 4x + 6x + 3 = 0 ⇒ (2x + 1) (4x + 3) = 0 ⇒ x = –1/2, –3/4

II. 10y² + 38y + 24 = 0 ⇒ 5y² + 19y + 12 = 0 ⇒ 5y² + 15y + 4y + 12 = 0 ⇒ (y + 3) (5y + 4) = 0 y = –3, –4/5 x > y
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