JEE Main 2022 · 29 Jul · Shift 2 · Mathematics Q15

MathematicsSingle correct+4 / -1Question 15 of 90

If (2, 3, 9), (5, 2, 1), (1, λ, 8) and (λ, 2, 3) are coplanar, then the product of all possible values of λ is :

\dfrac{21}2

\dfrac{59}8

\dfrac{57}8

\dfrac{95}8

Answer and worked solution

Official answer: D

Coplanarity. With A(2, 3, 9): $\begin{vmatrix}3&-1&-8\\-1&\lambda-3&-1\\\lambda-2&-1&-6\end{vmatrix}=8\lambda^2-57\lambda+95=0$ .

Product of roots $\frac{95}8$ .

(D)

Topics:Equation of a plane Determinants and properties

JEE Main 2022 · 29 Jul · Shift 2, Mathematics question 15