Question 2, Exercise 2.2

Solutions of Question 2 of Exercise 2.2 of Unit 02: Matrices and Determinants. This is unit of A Textbook of Mathematics for Grade XI is published by Khyber Pakhtunkhwa Textbook Board (KPTB or KPTBB) Peshawar, Pakistan.

Question 2(i)

Without evaluating state the reasons for the equalities. |120310−120|=0.

Solution

Given |120310−120|=0 Because elements of third column are zero.

Question 2(ii)

Without evaluating state the reasons for the equalities. |123−84−122−13|=0.

Solution

Given |123−84−122−13|=0 Taking −4 common from R2, we have −4|1232−132−13|=0 As elements of second and third rows are identical, so result is zero.

Question 2(iii)

Without evaluating state the reasons for the equalities. |13−23−11214|=|1323−11−214|.

Solution

Given |13−23−11214|=|1323−11−214| Right side is the transpose of left one.

Question 2(iv)

Without evaluating state the reasons for the equalities. |32011−324−6|=−3|320111242|.

Solution

Given |32011−324−6|=−3|320111242| Multiply −3 by third column of R.H.S.

Question 2(v)

Without evaluating state the reasons for the equalities. |10−13211−10|=−|10−11−10321|.

Solution

Given |10−13211−10|=−|10−11−10321| Interchanging the second and third rows on L.H.S.

Question 2(vi)

Without evaluating state the reasons for the equalities. |201312122|=|201556122|.

Solution

Given |201312122|=|201556122| Multiply the third row by 2 and add it in 2nd row of L.H.S to get R.H.S.

Go To

< Question 1 Question 3 >