a.
[tex]XA^{-1}=A^3[/tex]
[tex](XA^{-1})A=A^3A[/tex]
[tex]X(A^{-1}A)=A^4[/tex]
[tex]X=A^4[/tex]
b.
[tex]AXB=(BA)^2[/tex]
[tex]A^{-1}(AXB)B^{-1}=A^{-1}(BA)^2B^{-1}[/tex]
[tex](A^{-1}A)X(BB^{-1})=A^{-1}(BA)^2B^{-1}[/tex]
[tex]X=A^{-1}(BA)^2B^{-1}[/tex]
c.
[tex](A^{-1}X)^{-1}=(AB^{-1})^{-1}(AB^2)[/tex]
[tex]X^{-1}A=(BA^{-1})(AB^2)[/tex]
[tex]X^{-1}A=B(A^{-1}A)B^2[/tex]
[tex]X^{-1}A=B^3[/tex]
[tex](XX^{-1})A=XB^3[/tex]
[tex]XB^3=A[/tex]
[tex]X(B^3(B^3)^{-1})=A(B^3)^{-1}[/tex]
[tex]X=A(B^3)^{-1}[/tex]
d. Not totally sure what the equation is supposed to be, but I guess it's
[tex]ABXA^{-1}B^{-1}=A[/tex]
[tex]ABX(BA)^{-1}=A[/tex]
[tex]((AB)^{-1}(AB))X((BA)^{-1}(BA))=(AB)^{-1}A(BA)[/tex]
[tex]X=(AB)^{-1}A(BA)[/tex]
[tex]X=(B^{-1}A^{-1})A(BA)[/tex]
[tex]X=B^{-1}(A^{-1}A)(BA)[/tex]
[tex]X=(B^{-1}B)A[/tex]
[tex]X=A[/tex]