Matrices & Determinants · JEE Main previous year questions

2018 3 questions

1. Q52018 · 16 Apr 2018 · Shift 1

   The number of values of k for which the system of linear equations, (k + 2)x + 10y = k kx + (k +3)y = k -1 has no solution, is :

   1. A.1
   2. B.2
   3. C.3
   4. D.infinitely many
   Show answer

   Answer: A

2. Q42018 · 15 Apr 2018 · Shift 1

   Let A be a matrix such that $A\left[\begin{array}{cc}1& 2\\ 0& 3\end{array}\right]$ is a scalar matrix and $|3A|=108$. Then $A^2$ equals :

   1. A.$\left[\begin{array}{cc}4& -32\\ 0& 36\end{array}\right]$
   2. B.$\left[\begin{array}{cc}36& 0\\ -32& 4\end{array}\right]$
   3. C.$\left[\begin{array}{cc}4& 0\\ -32& 36\end{array}\right]$
   4. D.$\left[\begin{array}{cc}36& -32\\ 0& 4\end{array}\right]$
   Show answer

   Answer: D

3. Q22018 · 8 Apr 2018 · Shift 1

   If the system of linear equations $x+ky+3z=0$ $3x+ky-2z=0$ $2x+4y-3z=0$ has a non-zero solution (x, y, z), then $\frac{xz}{y^2}$ is equal to

   1. A.$30$
   2. B.$-10$
   3. C.$10$
   4. D.$-30$
   Show answer

   Answer: C