Question

Tính nhanh hộ mik nha!

A=1/2×1/3+1/3×1/4+1/4×1/5+1/5×1/6

Và bài này nữa

15÷x=0,85+0,35

Answer 1

1/2x3+1/3x4+1/4x5+1/5x6

= 1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6

=1/2-1/6

=1/3

15:x= 0.85+0.35

15:x= 1,2

    x= 15:1,2

     x= 12,5

nha bn, mk nghĩ vậy

Answer 2

Thank nhug dung ko

Answer 3

a) \(A=\frac{1}{2\times3}+\frac{1}{3\times4}+\frac{1}{4\times5}+\frac{1}{5\times6}\)

        \(=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\)

        \(=\frac{1}{2}-\frac{1}{6}\)

        \(=\frac{1}{3}\)

b)  \(15\div x=0,85+0,35\)

\(\Rightarrow15\div x=1,2\)

\(\Rightarrow x=15\div1,2\)

\(\Rightarrow x=12,5\)

Vậy \(x=12,5\)