I Don't understand what this matrix question is asking, help please!?

They are asking you to use the properties of determinants to calculate the value in (a). For example, the determinant of a product of matrices is the product of the determinants, the determinant of the inverse is the reciprocal of the determinant of the matrix itself, etc. So here the answer would be (No.1)^2(No.3)/(No.2)