3. )Question: 5 + 10 + 15 + 20 + 25 + 30 + 35. In sigma notation, it is ____________ and its sum is ___________.

Select your answer. 7 5n = 5) n; 28 7 7 E 5n = 5 \\ n; 140 n=2 C 3n =3 M- n; 140 n=1 n=1 7 5n = 5 n; 140 = 1