you can calculate the equivalent resistance by using Delta to Star method of R1 R2 and R5. Afterthat, you will get series and pallell resistances easily and you find get equilent resistance of the circuit.
If you transform R5 into 2 dependent current sources ( I=V/R5, where one terminal connect to the ground and the other terminal connect to the node), you can solve the equivalent resistance without knowing the "delta" transformation.