Given :

To find : x

Formula used :

Where c_ij = a_i1b_1j + a_i2b_2j + a_i3b_3j + ……………… + a_inb_nj

If A is a matrix of order a b and B is a matrix of order c d ,then matrix AB exists and is of order a d ,if and only if b = c

= 0

=

=

=

= ×

× =

× = =

= = 0

12x + 20 = 0

12x = -20

x = =

x =