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a fost răspuns

va rog e urgent !
1)calculati
a)2+4+6...250
b)1+3+5+7...299
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Va Rog E Urgent 1calculatia246250b1357299 class=

Răspuns :

a) 2+4+6+...+250=2×(1+2+...+125)=2×125×126/2=2×125×63=15750

b) 1+3+5+...+299=2×0+1+2×1+1+2×2+1+...+2×149+1=2×(0+1+2+...+149)+(1+1+...+1)=2×149×150/2+150=2×149×75+150=22500

10Karina

a)2(1+2+................................+125)

2*125*126:2⇒125*126=15750

b)(1+2+........................+299)-2(1+2+........+149)

299*300:2-2*149*150:2

44850-22350=22500

Alte intrebari