Solution:
We know,
is identity matrix of size \[3\]
So according to the given criteria
Now we will multiply the two matrices on LHS using the formula \[{{c}_{ij}}~=\text{ }{{a}_{i1}}{{b}_{1j}}~+\text{ }{{a}_{i2}}{{b}_{2j}}~+\text{ }\ldots \text{ }+\text{ }{{a}_{in~}}{{b}_{nj}},\] we get
And to satisfy the above condition of equality, the corresponding entries of the matrices should be equal
So we get
So the value of \[x\] is