Question

Find a and b if
$a\left[\begin{array}{c}1\\ 7\end{array}\right]-\left[\begin{array}{c}3\\ b\end{array}\right]=\left[\begin{array}{c}2\\ 24\end{array}\right]$

• A. a= -11, b = -5
  
• B. a= 11, b = 5
• C. a= -5, b = -11
  
• D. a= 5, b = 11

Answer 1

The correct option is D

a= 5, b = 11

$a\left[\begin{array}{c}1\\ 7\end{array}\right]-\left[\begin{array}{c}3\\ b\end{array}\right]=\left[\begin{array}{c}2\\ 24\end{array}\right]$

$=\left[\begin{array}{c}a\\ 7a\end{array}\right]-\left[\begin{array}{c}3\\ b\end{array}\right]=\left[\begin{array}{c}2\\ 24\end{array}\right]$
Equating the corresponding elements
$a-3=2a=57a-b=247\left(5\right)-b=24b=11$