What is the voltage at location A? (solve using any method)?

Let the location at which R1 , R4 and R8 are connected together be B ,

and the location at which R3 , R6 and R9 are connected together be C .

R1 = R3 , R4 = R6 and R8 = R9 , so the diagram is bilateral symmetry .

It means that the voltage at B and C are the same .

Therefore , B and C can be shorted without changing the condition .

If we do so , then the diagram becomes a bridge connection as below .

(Ri//Rj means the parallel connection of Ri and Rj .)

.... ------- 10V --------

.... | ........... ........... |

R1//R3 ................ R2

.... | ........... ........... |

.. BC --- R8//R9 --- A

.... | ........... ........... |

R4//R6 ................ R5

.... | ........... ........... |

.... -------- 0V ---------

Let the current from 10V to BC be i1 ,

let the current from 10V to A be i2 , and

let the current from A to BC be i3 .

The voltage difference BC to 10V = (R1//R3)*i1

The voltage difference A to 10V = R2*i2

The voltage difference BC to A = (R8//R9)*i3

So (R1//R3)*i1 = R2*i2 + (R8//R9)*i3 ---(#1)

The voltage difference 0V to BC = (R4//R6)*(i1 + i3)

So (R4//R6)*(i1 + i3) + (R1//R3)*i1 = 10 ---(#2)

The voltage difference 0V to A = R5*(i2 - i3)

So R5*(i2 - i3) + R2*i2 = 10 ---(#3)

Solve the simultaneous equations (#1) to (#3) , and find the voltage difference 0V to A .

That is left for you .