Question

[Lý Phạm Somali]

HELP!!!

Nhanh thì ấn đúng cho!~~

Answer 1

[Mới vô]

BÀI 1:

a)

\(\dfrac{1}{2}-\dfrac{2}{3}+\dfrac{3}{4}\\ =\dfrac{6}{12}-\dfrac{8}{12}+\dfrac{9}{12}\\ =\dfrac{6-8+9}{12}\\ =\dfrac{7}{12}\)

b)

\(-4\dfrac{1}{2}+1,2\cdot\left(-5\right)-30\%\\ =\dfrac{-9}{2}+\dfrac{6}{5}\cdot\left(-5\right)-\dfrac{3}{10}\\ =\dfrac{-9}{2}+\left(-6\right)-\dfrac{3}{10}\\ =\dfrac{-45}{10}+\dfrac{-60}{10}-\dfrac{3}{10}\\ =\dfrac{\left(-45\right)+\left(-60\right)-3}{10}\\ =\dfrac{-108}{10}\\ =\dfrac{54}{5}\)

c)

\(\dfrac{-7}{9}\cdot\dfrac{6}{13}+\dfrac{-7}{9}\cdot\dfrac{7}{13}+5\dfrac{7}{9}\\ =\dfrac{-7}{9}\cdot\left(\dfrac{6}{13}+\dfrac{7}{13}\right)+5\dfrac{7}{9}\\ =\dfrac{-7}{9}\cdot1+5\dfrac{7}{9}\\ =\dfrac{-7}{9}+5\dfrac{7}{9}\\ =5\)

Answer 2

[Mới vô]

BÀI 2

a)

\(\dfrac{3}{2}x-\dfrac{2}{3}=\dfrac{2}{3}:\dfrac{3}{2}\\ \dfrac{3}{2}x-\dfrac{2}{3}=\dfrac{4}{9}\\ \dfrac{3}{2}x=\dfrac{4}{9}+\dfrac{2}{3}\\ \dfrac{3}{2}x=\dfrac{10}{9}\\ x=\dfrac{10}{9}:\dfrac{3}{2}\\ x=\dfrac{20}{27}\)

b)

\(\left(\dfrac{9}{11}-x\right):\left(\dfrac{-10}{11}\right)=1-\dfrac{4}{5}\\ \left(\dfrac{9}{11}-x\right):\left(\dfrac{-10}{11}\right)=\dfrac{1}{5}\\ \dfrac{9}{11}-x=\dfrac{1}{5}\cdot\left(\dfrac{-10}{11}\right)\\ \dfrac{9}{11}-x=\dfrac{-2}{11}\\ x=\dfrac{9}{11}-\dfrac{-2}{11}\\ x=1\)

c)

\(\left(1,2x-\dfrac{4}{7}\right):\dfrac{4}{7}=75\%\\ \left(\dfrac{6}{5}x-\dfrac{4}{7}\right):\dfrac{4}{7}=\dfrac{3}{4}\\ \dfrac{6}{5}x:\dfrac{4}{7}-\dfrac{4}{7}:\dfrac{4}{7}=\dfrac{3}{4}\\ \dfrac{6}{5}x:\dfrac{4}{7}-1=\dfrac{3}{4}\\ \dfrac{6}{5}x:\dfrac{4}{7}=\dfrac{3}{4}+1\\ \dfrac{6}{5}x:\dfrac{4}{7}=\dfrac{7}{4}\\ \dfrac{6}{5}x=\dfrac{7}{4}\cdot\dfrac{4}{7}\\ \dfrac{6}{5}x=1\\ x=1:\dfrac{6}{5}\\ x=\dfrac{5}{6}\)