Answer:
y = 17
Step-by-step explanation:
3(y-13)=13
3y-39=12
3y=51
y=17
3[y-13] = 12
3*y + 3*-13 = 12
3y - 39 = 12
3y = 12 + 39
3y = 51
y = 51/3
Check:
3[17-13] = 12
3*4 = 12
