Question

1/2+1/6+1/12+1/20+1/30+1/x=41/42

 giai giup minh cau nay nhe

Answer 1

x = 7 . đúng 100%. chọn mình nha.

Answer 2

\(\frac{1}{x}=\frac{41}{42}-\frac{1}{30}-\frac{1}{20}-\frac{1}{12}-\frac{1}{6}-\frac{1}{2}\)

\(\frac{1}{x}=\frac{1}{7}\). Suy ra \(x\)= 7.

Answer 3

1/2 +1/6 +1/12+1/20+1/30+1/x=41/42

Ta có \(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+\frac{1}{5\cdot6}+\frac{1}{6\cdot7}=\frac{41}{42}\)

mà 6 . 7 bàng 42=> x=42

mà . là dấu nhân