# 10th Maths Book Back Algebra Ex 3.18

## Samacheer Kalvi 10th Maths Book Back Solution:

Tamil Nadu 10th Maths Book Back Answers Unit 3 – Algebra Ex 3.18 are provided on this page. Samacheer Kalvi Maths Book Back Solutions/ Guide available for all Units. TN Samacheer Kalvi 10th Maths Book consists of 8 Units and each unit book back solutions given below topics wise with Questions and Answers. The complete Samacheer Kalvi Books Back Answers/Solutions are available on our site.

The Samacheer kalvi 10th Maths solutions are useful to enhance your skills. Candidates who prepared for the Competitive and board exams 10th Maths Book Back Answers in English and Tamil Medium. The 10th Maths Unit 3 Algebra consists of 19 units. Each Unit Book Back Answers provide topic-wise on this page. 10th Maths Book Back Answers are prepared according to the latest syllabus. The 10th Maths Book Back Algebra Ex 3.15 Answers in English.

### 10th Maths Book Back Answers/Solutions:

TN Samacheer Kalvi 10th Maths Unit 3 Chapter 18 Book Back Exercise has given below. The 10th Maths Book Back Solutions Guide is uploaded below.

### Exercise 3.18 Algebra

1. If A is of order p × q and B is of order q × r what is the order of AB and BA?
Solution:
If A is of order p × q [∵ p × q q × r = p × r]
the order of AB = p × r [∵ q × r p × q = r ≠ p]
Product of BA cannot be defined/found as the number of columns in B ≠. The number of rows in A.

2. If A is of order p × q and B is of order q × r what is the order of AB and BA?
Order of A = a × (a + 3)
Order of B = b × (17 – b)
Given: Product of AB exist
a + 3 = b
a – b = – 3 ….(1)
Product of BA exist
17 – b = a
– a – b = -17
a + b = 17 ………(2)
(1) + (2) ⇒ 2a = 14
a = 142 = 7
Substitute the value of a = 7 in (1)
7 – b = -3 ⇒ -b = -3 -7
-b = -10 ⇒ b = 10
The value of b = 7 and b = 10

3. Find the order of the product matrix AB if Solution: 4.If A = , B = [12−35] find AB, BA and check if AB = BA?
Solution: 5. Solution:   6.Show that the matrices A = , B = [1−3−21] satisfy commutative property AB = BA
Solution: 7. (i) A(BC) = (AB)C
(ii) (A – B)C = (AC – BC)
(iii) (A- B)T = AT – BT
Solution:
(i) A(BC) = (AB)C    8. Solution: 9. 10.Verify that A2 = I when A = (56−4−5)
Solution: 12. 13.If A =  show that A2 – 5A + 7I2 = 0.
Solution: 