Please solve RD Sharma class 12 chapter Solution of Simultaneous Linear Equation exercise 7.1 question 21 maths textbook solution
According to the question
X=A-1B is used to solve this problem.
And the determinant and co-factor of matrix A, take it’s transpose that will be Adj A using Adj A calculate A-1.
As there are 3 variables of pen A, B, C
Meenu purchased a pen of each variety which costs her Rs21
Cost of A variety of pens= Rs5
Cost of B variety of pens= Rs8
Cost of C variety of pens= Rs8