Answer:
[tex]\dfrac 3{10}[/tex]
Step-by-step explanation:
[tex]~~~~~~\dfrac 25 + x = \dfrac 7{10}\\\\\\\implies x = \dfrac 7{10} - \dfrac 25\\ \\\\\implies x = \dfrac 7{10} - \dfrac 4{10}\\\\\\\implies x = \dfrac{7-4}{10}\\\\\\\implies x = \dfrac 3{10}[/tex]
