Question

13. Calculați:
a) |-1| + |-2| + |-3|+.....+ |-50|
b) |-3| + |-6| + |-9| +....+ |-90|
c) |+2| + |+5| + |+8|+.....+|+29|
d) |-2|¹ + |-2|² + ...... + |-2|²⁰
am nevoie de ajutor! dacă ma puteți ajuta va mulțumesc si va dau 5 stele​

Answer 1

|-1| + |-2| + |-3|+.....+ |-50|=1+2+3+...+50=51*50/2+1=51*25+1=1275+1=1276

|-3| + |-6| + |-9| +....+ |-90|=3+6+9+...+90=3*(1+2+3+...+30)=3*31*30/2+1=3*31*15+1=1395+1=1396

|+2| + |+5| + |+8|+.....+|+29|=2+5+8+...+29=155

|-2|¹ + |-2|² + ...... + |-2|²⁰=2¹ + 2² + ...... + 2²⁰=2+4+8+...+1048573=2*(1+2+4+...+524288)