If A = [3 5], B = [7 3], then find a non-zero matrix C such that AC = BC.

We have the matrices A and B, such that



We need to find matric C, such that AC = BC.


Let C be a non-zero matrix of order 2 × 1, such that



But order of C can be 2 × 1, 2 × 2, 2 × 3, 2 × 4, …


[ In order to multiply two matrices, A and B, the number of columns in A must equal the number of rows in B. Thus, if A is an m x n matrix and B is an r x s matrix, n = r.


, number of columns in matrix A = number of rows in matrix C = 2]


Take AC.



Multiply 1st row of matrix A by matching members of 1st column of matrix C, then sum them up.


(3, 5)(x, y) = (3 × x) + (5 × y)


(3, 5)(x, y) = 3x + 5y




Now, take BC.



Multiply 1st row of matrix B by matching members of 1st column of matrix C, then sum them up.


(7, 3)(x, y) = (7 × x) + (3 × y)


(7, 3)(x, y) = 7x + 3y




And,


AC = BC


[3x + 5y] = [7x + 3y]


3x + 5y = 7x + 3y


7x – 3x = 5y – 3y


4x = 2y


y = 2x


Then,



Since, C is of orders, 2 × 1, 2 × 2, 2 × 3, …



In general,



Where, k is any real number.


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