\(\dfrac{2}{5}-\left(\dfrac{1}{10}-x\right)=\left(\dfrac{-4-5}{10}\right)^2\\ \dfrac{2}{5}-\left(\dfrac{1}{10}-x\right)=\left(-\dfrac{9}{10}\right)^2\\ \dfrac{2}{5}-\left(\dfrac{1}{10}-x\right)=\dfrac{81}{100}\\ \dfrac{1}{10}-x=\dfrac{2}{5}-\dfrac{81}{100}\\ \dfrac{1}{10}-x=\dfrac{20.2-81}{100}\\ \dfrac{1}{10}-x=-\dfrac{41}{100}\\ x=\dfrac{1}{10}-\left(-\dfrac{41}{100}\right)\\ x=\dfrac{10+41}{100}\\ x=\dfrac{51}{100}\)
`2/5 - (1/10 - x) = (-2/5 - 1/2)^2`
`=> 2/5 - (1/10 - x) = (-9/10)^2`
`=> 2/5 - (1/10 - x) = 81/100`
`=> 1/10 - x = 2/5 - 81/100`
`=> 1/10 - x = -41/100`
`=> x = 1/10 + 41/100`
`=> x = 51/100`