Question

giúp mình 2 bài trên nha

Answer 1

a, \(\dfrac{x}{7}=\dfrac{18}{14}\)

\(\Leftrightarrow14x=18.7\)

\(\Rightarrow14x=126\)

\(\Rightarrow x=126:14\)

\(\Rightarrow x=9\)

\(b,6:x=1\dfrac{3}{4}:5\)

\(6:x=1,75:5\)

\(\Rightarrow\dfrac{6}{x}=\dfrac{1,75}{5}\)

\(\Leftrightarrow1,75x=6.5\)

\(\Rightarrow1,75x=30\)

\(\Rightarrow x=30:1,75\)

\(\Rightarrow x=\dfrac{120}{7}\)

c, \(5,7:0,35=\left(-x\right):0,45\)

\(\dfrac{5,7}{0,35}=\dfrac{\left(-x\right)}{0,45}\)

\(\Leftrightarrow0,35\left(-x\right)=5,7.0,45\)

\(\Rightarrow-0,35x=2,565\)

\(\Rightarrow x=2,565:\left(-0,35\right)\)

\(\Rightarrow x=2,215\)

Answer 2

a, x/7=18/14

x/7=9/7

=>x=9

b, 6:x=1+3/4 : 5

6:x=7/4 : 5

6:x=7/20

x=6 : 7/20

x=120/7

c, 5,7 : 0,35=(-x) : 0,45

114/7=(-x) : 0,45

-x=114/7 * 0,45

-x=513/70

x=-(513/70)

Answer 3

a)\(\dfrac{x}{7}=\dfrac{18}{14}\)

\(\dfrac{x}{7}=\dfrac{9}{7}\) suy ra x=9

b)6:x=\(1\dfrac{3}{4}:5\)

6:x=\(\dfrac{7}{20}\)

x=6:\(\dfrac{7}{20}\)

x=\(\dfrac{120}{7}\)