Determine the values of a and b so that the following matrices are singular:
A = `[(7,3),(-2,a)]`

Determine the values of a and b so that the following matrices are singular: B=[(b-1,2,3),(3,1,2),(1,-2,4)]

Find k,if the following matrices are singular: [[7,3],[-2,k]]

Find a, so that the following matrix is singular [[a,2],[a,3]]