\(a,11-\left(\dfrac{2}{5}+x\right)=12\dfrac{2}{3}\\ 11-\left(\dfrac{2}{5}+x\right)=\dfrac{38}{3}\\ \dfrac{2}{5}+x=11-\dfrac{38}{3}=\\ \dfrac{2}{5}+x=\dfrac{-5}{3}\\ x=\dfrac{-5}{3}-\dfrac{2}{5}\\ x=\dfrac{-31}{15}\)
\(b,\left(x-\dfrac{1}{2}\right)^3=\dfrac{1}{27}\\ \left(x-\dfrac{1}{2}\right)^3=\left(\dfrac{1}{3}\right)^3\\ x-\dfrac{1}{2}=\dfrac{1}{3}\\ x=\dfrac{1}{3}+\dfrac{1}{2}\\ x=\dfrac{5}{6}\)
a)11-(2/5+x)=12+2/3
=11-2/5-x=38/3
x=11-2/5-38/3=-31/15
b)1/27=(1/3)^3=(x-1/2)^3
=>x-1/2=1/3=>x=1/3+1/2=5/6