JEE mathematics

If α, β are the roots of x² - p(x+1) - c = 0, then find the value of (α + 1)(β + 1) — JEE Mathematics

SSandeepRanasinghe88 Asked 1mo ago 1,516 views 1 answer

If $\alpha, \beta$ are the roots of $x^2 - p(x+1) - c = 0$, then find the value of $(\alpha + 1)(\beta + 1)$.

1 Answer

VAVidaara Admin ✓ Vidaara Team ✓ Accepted · 1mo ago ▲ 27

Rewrite the given equation in standard form:

$$x^2 - px - (p + c) = 0$$

From the coefficients, we can find the sum and product of the roots:

$$\alpha + \beta = p$$

$$\alpha\beta = -(p + c)$$

Now expand the expression we want to evaluate:

$$(\alpha + 1)(\beta + 1) = \alpha\beta + \alpha + \beta + 1$$

Substitute the values of $\alpha + \beta$ and $\alpha\beta$:

$$(\alpha + 1)(\beta + 1) = -(p + c) + p + 1 = -p - c + p + 1 = 1 - c$$

Answer: $1 - c$

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Discussion (3)

S
Is there a faster shortcut for this in the actual exam? Time is tight.
SophiaMiller84 · 1mo ago
L
Brilliant explanation, the substitution step is what I kept missing.
LiamAnderson39 · 30d ago
VA
Great discussion here. If you want more practice on this concept, check the related questions in this category.
Vidaara Admin · Vidaara Team · 29d ago
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