Số số hạng của dãy số là:

10-0+1=11(số)

Tổng của dãy số là: \(\left(10+0\right)\times\frac{11}{2}=10\times\frac{11}{2}=5\times11=55\)

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1+2+3+4+5+6+7+8+9+10+11=66

1+2+3+4+5+6+7+8+9+10+11=66

Tui không biết nha giúp tui làm

550 bạn nhé

[(1+9)+(2+8)+(3+7)+(4+6)+5]x2

=(10+10+10+10+5)x2

=45x2

=90

50x2+2x10

=2x(50+10)

=2x60

=120

\(x = {-b \pm \sqrt{b^2-4ac} \over 2a}\)

=90

k nha

=90

k nha

mình cần lắm thanks

1+2+3+4+5+6+7+8+9+1+2+3+4+5+6+7+8+9+0+0+0+3+4+1+2+3+111+44+99 = 357

1+2+3+4+5+6+7+8+9+1+2+3+4+5+6+7+8+9+0+0+0+3+4+1+2+3+111+44+99=357

11-10+9-8+7-6+5-4-3-2+1=0

1 + 1 + 2 + 2 + 3 + 3 + 4 + 4 + 5 + 5 + 6 + 6 + 7 + 7 + 8 + 8 + 9 + 9 +10 +10  

= (1+9) + (1+9) + (2+8) + (2+8) + (3+7) + (3+7) + (4+6) + (4+6) + (5+5) + 10+10

= 10 + 10 +10 + 10 +10 +10 +10 +10 + 10 + 10 +10

= 10 x 11

= 110

110

1+2+3+4+5+6+7+8+9+0+0+0+0+0+0+9+8+7+6+5+34+2+3+5=124

mik trả lời đầu k mik nha

124 k mình nhé