Respuesta :

pegah
you should just add -7 in both sides of the equation so you gonna have : 
y + 7 = 10 
   -7       -7   
so you gonna have : y = 10- 7  and y = 3 :))
i hope this is helpful 
have a nice day 
Subtract from both sides to isolate the variable. (inverse operation)

y+7 = 10
   -7     -7

y = 3

Final answer: y = 3
good job