Form
Number and gender
Natural meaning
فَعَلْتَ
masculine singular
you (one man) did
فَعَلْتُمَا
masculine dual
you two men did
فَعَلْتُمْ
masculine plural
you men did
فَعَلْتِ
feminine singular
you (one woman) did
فَعَلْتُمَا
feminine dual
you two women did
فَعَلْتُنَّ
feminine plural
you women did
The same form فَعَلْتُمَا addresses two people whether they are masculine or feminine; context supplies the gender.