Ajutor!Sunt clasa a v-a!Va rog frumos sa ma ajutati la urmatorul exercitiu:
Gasiti numarul natural x care verifica egalitatea:
a)1+2+3+...+10+x=3000
b)1+2+3+4+x+6+7+8+9=550

2
a)1+2+3+...+10+x=3000
10*11:2+x=3000
55+x=3000
X=3000-55
X=2945

b)1+2+3+4+x+6+7+8+9=550
9*10:2-5+x=550
45-5+x=550
X=550-40
X=510
Am folosit suma lui Gauss: 1+2+3+……..+n=n*(n+1):2

Răspunsuri

Cel mai inteligent răspuns!
2014-09-30T23:25:07+03:00
1+2+3+..+10+x=3000
=> (10·11): 2 +x=3000
=>55+x=3000
=>x=3000-55=2945

1+2+3+4+x+6+7+8+9=550
=>(1+9)+(2+8)+(3+7)+(4+6)+x=550
=>10+10+10+10+x=550
=>40+x=550
=>x=510
2 3 2
2014-09-30T23:38:18+03:00
A)55+x=3000
x=3000-55=2945
b)40+x=550
x=550-40=510