If A= [ ll 1 & 1 8 & 3 ], then A^2-4 A= - Vidyadip

MCQ

If $A=\left[\begin{array}{ll}1 & 1 \\ 8 & 3\end{array}\right]$, then $A^2-4 A=$

A
$\left[\begin{array}{rr}-3 & -3 \\ 60 & 5\end{array}\right]$
B
$\left[\begin{array}{rr}-3 & -3 \\ 8 & 3\end{array}\right]$
✓
$\left[\begin{array}{ll}5 & 0 \\ 0 & 5\end{array}\right]$
D
$\left[\begin{array}{cc}8 & 3 \\ 24 & 14\end{array}\right]$

✓

Answer

Correct option: C.

$\left[\begin{array}{ll}5 & 0 \\ 0 & 5\end{array}\right]$

(c) $\left[\begin{array}{ll}5 & 0 \\ 0 & 5\end{array}\right]$
Explanation:
$\begin{array}{l} A ^2-4 A= A \cdot A -4 A \\ =\left[\begin{array}{ll}1 & 1 \\ 8 & 3\end{array}\right]\left[\begin{array}{ll}1 & 1 \\ 8 & 3\end{array}\right]-4\left[\begin{array}{ll}1 & 1 \\ 8 & 3\end{array}\right] \\ =\left[\begin{array}{cc}9 & 4 \\ 32 & 17\end{array}\right]-\left[\begin{array}{cc}4 & 4 \\ 32 & 12\end{array}\right] \\ =\left[\begin{array}{ll}5 & 0 \\ 0 & 5\end{array}\right]\end{array}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "MCQ" from Matrices→Matrices — all question types→Mathematics STD 10 question papers→ICSE Board STD 10 question papers→ICSE Board question paper generator→

Similar questions

The solution of the equation $x^2+x+1=1$ is:

Which of the following is a diagonal matrix ?

The ratio of 45 minutes to $5 \frac{3}{4}$ hours is

Statement (A): The 10th term of the AP $8,10,12, \ldots 126$ is 36
Statement (B): The sum of the 10th terms of the AP 8, 10, 12, ..., 126 is 170
Which of the statement is valid?

Manisha deposited ₹ $500$ per month in a recurring deposit account for 2 years. If the bank pays interest at $8 \%$ p.a., then the interest she gets at the time of maturity is :

If $-x \geq 5$ and $-a x \geq 5 a$, then :

The fourth proportional to 3, 6 and 4.5 is :

$........$ term of the $G.P. 18,12,8, \ldots$ is $\frac{512}{729}$.

Ruhi deposited 200 per month for 15 months in a bank's recurring deposit account. If the bank pays interest at a rate of 10% per annum, then the interest earned by Ruhi during this period is:

Anita buys 400, twenty rupees shares at a discount of 20% and receives a return of 12% on his money. Calculate the amount invested by her: