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3. Numărul natural x care verifică 2 + 4 + 6 +
..... +2018 = 2019 × x -(1 + 3 + 5 + ... +2019) este:


Răspuns :

Răspuns:

2(1+2+3+...+1009)=2019*x-(1+2+3+...+2019)+2(1+2+3+...+1009)

2*1009*1010/2=2019*x-(2019*2020/2)+2*1009*1010/2

1009*1010=2019*x-2019*1010+1009*1010

2019*x=1009*1010+2019*1010-1009*1010

2019*x=1010*2019

x=1010

Răspuns:

2+4+6+...+2018=

2019:3=673

[(2018+2)×673]:2

(2020×673):2

1359460:2

679730

679730=2019 × x -(1 + 3 + 5 + ... +2019)

2019×x-(1+3+5+...+2019)

2019×x-2019×(2019+1):2

2019×(x-2020:2)

2019×(x-1010)=679730

x-1010=679730:2019

x-1010=336

x=336+1010

x=1346

Sper ca team ajutat!