=7

Hok tốt

1 + 2 -1 +5 =7

=9 nh

k mk nữa nh roi mk k cho bn nh

9+1-2

=10-2

=8

CHÚC BẠN HỌC TỐT!

9+1-2=8

Hok tốt

#EMNA#

=8

Hoc~Tot

trả lời

2+3-1=4

chc bn hok giỏi

////////

2 + 3 - 1 = 4

trả lời

2+3-1=4

học tốt

DNMT :P

60 : 2 = 30

30 : 6 = 5

10 : 2 = 5

60 : 2 = 30

30 : 6 = 20

10 : 2 = 5

60 :2=30

30:6=5

10:2=5

(n+1)²-n²=(n+1)*(n+1)-n²

                  =n²+n+n+1-n²

             =n²-n²+n+n+1

             =0+2n+1=2n+1

B=\(1+3^2+3^4+...+3^{100}\)

9B=\(3^2+3^4+...+3^{100}\)

9B-B=\(\left(3^2+3^4+...+3^{102}\right)-\left(1+3^2+3^4+...+3^{100}\right)\)

8B=\(3^{102}-1\)

B=\(\left(3^{102}-1\right):8\)

C=\(1+5^3+5^6+...+5^{99}\)

125C=\(5^3+5^6+5^9+...+5^{102}\)

125C-C=\(\left(5^3+5^6+5^9+...+5^{102}\right)-\left(1+5^3+5^6+...+5^{99}\right)\)

124C=\(5^{102}-1\)

C=\(\left(5^{102}-1\right):124\)

1 + 1 + 2 + 3 = 7

 kết quả 7 nhé bạn k minh nhé love you

1+1+2+3=7

\(3B=\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{100.103}.\)

\(3B=\frac{4-1}{1.4}+\frac{7-4}{4.7}+\frac{10-7}{7.10}+...+\frac{103-100}{100.103}\)

\(3B=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{100}-\frac{1}{103}=1-\frac{1}{103}=\frac{102}{103}\)

\(B=\frac{102}{3.103}=\frac{34}{103}\)

B=\(\frac{1}{1.4}+\frac{1}{4.7}+\frac{1}{7.10}+......+\frac{1}{100.103}\)

B=\(\frac{1}{3}.\left(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+....+\frac{3}{100.103}\right)\)

B=\(\frac{1}{3}.\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+......+\frac{1}{100}-\frac{1}{103}\right)\)

B=\(\frac{1}{3}.\left(1-\frac{1}{103}\right)\)

B=\(\frac{1}{3}.\frac{102}{103}\)

B=\(\frac{34}{103}\)