a) Suma lui gauss este data de formula Sn= [(a1+an)×n]/2
S1= -2(1+2+3+....+100)= -2[(1+100)×100]/2 = -[101×100]= -10100
S2= -3(1+2+3+....+200)= -3[(1+200)×200]/2 = -3[201×100]= -3×20100= -60300
S1+S2= -10100-60300= -70400
b) S1= -5(1+2+3+....+100)= -5[(1+100)×100]/2= -5[101×50]= -25250
S2= 6(1+2+3+....+50)= 6[(1+50)×50]/2 = 3[51×50]= 3×2550= 7650
S1+S2= -25250+7650= -17600