Q8 of 75 Page 8

Solve the following questions.

Given , find BA and use this to solve the system of equations y + 2z = 7, x – y = 3, 2x + 3y + 4z = 17

B = A =

BA =


BA =


Now, we can see that it is BA = 6I. where I is the unit Matrix


Or, B – 1 =


Now the given equation can be written as:



A X B


Or, X = B – 1A


=



=


X =


Hence, x = – 8,y = – 15 and z =


More from this chapter

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8

Solve the following questions.

, find AB. Hence, solve the system of equations:


x – 2y = 10, 2x + y + 3z = 8 and – 2y + z = 7

 8

Solve the following questions.

If , find A – 1. Using A – 1, solve the system of linear equations


x – 2y = 10, 2x – y – z = 8, – 2y + z = 7.

 9

The sum of three numbers is 2. If twice the second number is added to the sum of first and third, the sum is 1. By adding second and third number to five times the first number, we get 6. Find the three numbers by using matrices.

 10

An amount of ₹10,000 is put into three investments at the rate of 10, 12 and 15% per annum. The combined incomes are ₹1310 and the combined income of first and second investment is ₹ 190 short of the income from the third. Find the investment in each using matrix method.