sum_(r=0)^100=(8-3r)/16= sum_(r=0)^100 8/16 - (3r)/16100∑r=0=8−3r16=100∑r=0816−3r16
=sum_(r=0)^100 1/2 -3/16* sum_(r=0)^100 r=100∑r=012−316⋅100∑r=0r or
[sum_(r=0)^n=(n(n+1))/2][n∑r=0=n(n+1)2]
sum_(r=0)^100=1/2*101 - 3/16* (100*101)/2100∑r=0=12⋅101−316⋅100⋅1012
sum_(r=0)^100=50.5 - 3/16* 5050100∑r=0=50.5−316⋅5050 or
sum_(r=0)^100=50.5 - 946.875= -896.375100∑r=0=50.5−946.875=−896.375 [Ans]