How would I find the RMM of the unknown metal if the molarity of HCl = 0.1 M , NaOH = 0.1
The Metal was dissolved in 80 cm3 of HCL and titrated against 22. 74 cm3 of NaOH. The mass of the metal was 0.0686 g.

You added 80 cc (mL) of 0.1M HCl. That is 8 mmoles.

You back-titrated with 22.73 cc (mL) of 0.1M NaOH. That's 2.273 mmoles.

8 - 2.273 = 5.727 mmoles

You don't know the metal but you know that there are 5.727 milliequivalents of it present.

5.727 milliequivalents / 0.0686 g = 83.484 milliequivalents / g

or

0.083484 equivalents / gram

Now, I don't know what RMM means, so you'll have to figure that part out.