Question

1/7 - ( 5/21 - x ) = 7/3

5,16 - 2x = ( 5,7 + 2,3 ) * ( - 0,3 )

Answer 1

\(\dfrac{1}{7}-\left(\dfrac{5}{21}-x\right)=\dfrac{7}{3}\)

\(\Rightarrow\dfrac{5}{21}-x=\dfrac{1}{7}-\dfrac{7}{3}\)

\(\Rightarrow\dfrac{5}{21}-x=-\dfrac{46}{21}\)

\(\Rightarrow x=\dfrac{5}{21}+\dfrac{46}{21}\)

\(\Rightarrow x=\dfrac{17}{7}\)

__________________

\(5,16-2x=\left(5,7+2,3\right)\cdot\left(-0,3\right)\)

\(\Rightarrow5,16-2x=8\cdot\left(-0,3\right)\)

\(\Rightarrow5,16-2x=-2,4\)

\(\Rightarrow2x=5,16+2,4\)

\(\Rightarrow2x=7,56\)

\(\Rightarrow x=3,78\)

Answer 2

a: =>5/21-x=1/7-7/3=3/21-49/21=-46/21

=>x=5/21+46/21=51/21=17/7

b: =>5,16-2x=8*(-0,3)=-2,4

=>2x=5,16+2,4=7,56

=>x=3,78