Question 6
Matrices and DeterminantsFind y if
( 5 −6 )( x ) = ( 7 )
( 2 −7 )( y ) ( −11 )
- A.2
- B.8
- C.5
- D.3
Show the answer and explanation
Answer: D (3)
Explanation
The matrix equation gives 5x − 6y = 7 and 2x − 7y = −11. Multiply the first by 2 and the second by 5 and subtract: 23y = 69, so y = 3.