algebra
posted by babygirl on .
solve using the multiplication principle 3a<15
solve usins addition and multiplication 3c+4<6
3c+44<6+4
3c<2
3c/3<2/3
c<2/3 is this right

No.
Your error is in this line:
3c+44<6+4
You should subtract 4 from both sides.
6 and 4 = 10