Multiple choice

If $\alpha$ and $\beta$ are roots of the quadratic equation $x^2-2x+3=0$ then quadratic equation whose roots are $\displaystyle \frac{\alpha -1}{\alpha +1}, \frac{\beta -1}{\beta +1}$.

  1. $\displaystyle 3x^{2}+2x+1= 0.$
  2. $\displaystyle 3x^{2}-2x+1= 0.$
  3. $\displaystyle 2x^{2}-3x-1= 0.$
  4. None of these

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let y = (x-1)/(x+1). Then x = (1+y)/(1-y). Substituting into x^2 - 2x + 3 = 0 gives ((1+y)/(1-y))^2 - 2((1+y)/(1-y)) + 3 = 0. Simplifying leads to 3y^2 - 2y + 1 = 0.

AI explanation

From the equation x^2 - 2x + 3 = 0, the sum of the roots is alpha + beta = 2 and the product is alpha * beta = 3. Let the new root be y = (x - 1)/(x + 1), which rearranges to x = (1 + y)/(1 - y). Substituting this expression for x into the original quadratic equation yields ((1 + y)/(1 - y))^2 - 2((1 + y)/(1 - y)) + 3 = 0. Clearing the denominator by multiplying by (1 - y)^2 and simplifying the algebraic expansion gives the new equation 3y^2 - 2y + 1 = 0.