R1 is in series with the restHow would you write it?
Req = R1 + [???]
R8 is in parallel with resistors on the left and resistors on the right. Do one at a time.
R11 = R2//R3
R10 = R8//( R11 + R4)
R9 = R7 + R10
See if you can write out the equation for Req using R5, R6, R9
Req = R1 + [ ???]