Had a MRI done came back with r lesion, multiple subcentimeter cyst both breast. Impression says birads 3 mother had b cancer. What is birad 3?

Probably benign. The examination has a 97% likelihood of being benign (no malignancy in either breast.) the recommendation for a birads 3 report is to repeat the examination in 6 months.
likely benign. American cancer society:category 3: probably benign finding – follow-up in a short time frame is suggested the findings in this category have a very good chance (greater than 98%) of being benign (not cancer). The findings are not expected to change over time. But since it’s not proven benign, it’s helpful to see if an area of concern does change over time. Follow-up with repeat imaging is usual.