Question

a) X + = 4/5 : 2/3           b)  4/7 x 8/13 + 8/13 x 3/7

Answer 1

a) Thiếu đề

b) ` 4/7 xx 8/13 + 8/13 xx 3/7`

= ` 8/13 xx ( 4/7 + 3/7)`

` = 8/13 xx 7/7`

` = 8/13 xx 1`

` = 8/13`

Answer 2

a) thiếu đề

b) \(=\left(\dfrac{4}{7}+\dfrac{3}{7}\right)\times\dfrac{8}{13}\\ =1\times\dfrac{8}{13}=\dfrac{8}{13}\)

Answer 3

Answer 4

\(a,x+\alpha=\dfrac{4}{5}:\dfrac{2}{3}\\ x+\alpha=\dfrac{6}{5}\\ x=\dfrac{6}{5}-\alpha\)

Bạn thay vào rồi tính nhé :)

\(b,\dfrac{4}{7}\times\dfrac{8}{13}+\dfrac{8}{13}\times\dfrac{3}{7}\\ =\dfrac{8}{13}\times\left(\dfrac{4}{7}+\dfrac{3}{7}\right)=\dfrac{8}{13}\times1\\ =\dfrac{8}{13}\)

Answer 5

b)\(\dfrac{4}{7}x\dfrac{8}{13}+\dfrac{8}{13}x\dfrac{3}{7}=\dfrac{8}{13}x\left(\dfrac{4}{7}+\dfrac{3}{7}\right)=\dfrac{8}{13}x1=\dfrac{8}{13}\)