if alpha and beta are the zeros of a quadratic polynomial x square - 2 X + 3 find a polynomial whose roots are 1. alpha + beta, beta + Alpha 2.alpha-1/alpha+1,beta-1/beta+1
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Let α, β be the roots of the equation
x² - 2x + 3 = 0
Let f(x) = x² - 2x + 3
★ Given:-
- Roots are increased by 2, so new roots of the equation are α + 2, β + 2.
- Let y = α + 2 which is the required root of new
So, α = y - 2
But, we know α is root of f(x), therefore
f(α) = 0
But α = y - 2, so
f(y - 2) = 0
(y - 2)² - 2(y - 2) + 3 = 0
y² - 6y + 11 = 0,
★ Point to remember:-
Since similar argument hold for other root as well, hence this equation represents the one with roots α + 2 and β + 2.
Changing the variable y to x, we get,
x² - 6x + 11 = 0, which is the required equation.
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