Question

Giải hộ 

3/1.4 + 3/4.7 + 3/7.10 + ...... +3/40.43

Phải tính nhanh nha!

Ai nhanh nhất cho 1000000000000000000000000000000000000000000000000000000000000 like luôn!!!!!!!!!!!!!!!

Nhanh nha đang làm đề cương

Answer 1

3/1.4+3/4.7+3/7.10+......+3/40.43

=1/1-1/4+1/4-1/7+1/7-1/10+......+1/40-1/43

triệt tiêu hết cho nhau ta còn:

1/1-1/43=43/43-1/43=42/43

nhớ cho mình nhé

Answer 2

\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+....+\frac{3}{40.43}\)

\(=1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{40}-\frac{1}{43}\)

\(=1-\frac{1}{43}\)

\(=\frac{42}{43}\)

Answer 3

Sao ở trên /3 xuống lại có 1 vậy??

Answer 4

\(\frac{3}{1.4}+\frac{3}{4.7}+\frac{3}{7.10}+...+\frac{3}{40.43}\)

\(=\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+...+\frac{1}{40}-\frac{1}{43}\)

\(=\frac{1}{1}-\frac{1}{43}\)

\(=\frac{42}{43}\)