У-31=21

To solve the equation, we need to isolate the variable "у". Here's how you can do it:

у - 31 = 21

First, you can start by adding 31 to both sides of the equation to isolate "у" on the left side:

у - 31 + 31 = 21 + 31

Simplifying both sides:

у = 52

So the value of у in the equation is 52.